explain xkcd - User contributions [en]

2701: Change in Slope

2022-11-24T00:21:09Z

172.69.34.44: fixed residuals, added slope standard error comparison

{{comic
| number = 2701
| date = November 21, 2022
| title = Change in Slope
| image = change_in_slope_2x.png
| imagesize = 656x371px
| noexpand = true
| titletext = Squinting at a graph is fine for getting a rough idea of the answer, but if you want to pretend to know it exactly, you need statistics.
}}

==Explanation==
{{incomplete|Created by a SIDEWAYS STATISTIC. Do NOT delete this tag too soon.}}

The comic is a tip for detecting changes in slopes over a {{w|scatter plot}} of data. This is a common requirement in exploratory statistics for comparing trends in a series — finding the cutoff where the slope changes may reveal valuable information about the data.

The comic compares two methods. Firstly, a novice method — by 'doing a bunch of statistics'- i.e, applying various statistical tools to analyze the data and figure out the quantitative change in slope. This results in two equations for the trendlines above and below a given value, a box plot, a histogram, and a line chart. It is unknown exactly what methods the novice used to figure out the change in slope in the data. Possibilities include calculating the [https://stackoverflow.com/a/45063636 derivatives] (which probably won't work well on noisy data such as shown), or [https://stackoverflow.com/a/71744293 gradients], or using a [https://stackoverflow.com/a/47522444 Savitzky-Golay filter or piecewise linear smoothing spline fits]. [[Randall]]'s light gray figures may be suggesting [https://colab.research.google.com/drive/1apKDIN5FE32mtGiQew5cE6wK6m6eM_Fr this method.]

The other is the so-called 'expert' method, which involves [https://cdn.discordapp.com/attachments/525939879805190154/1044395695525875712/xkcd_sideways.png tilting the page the graph is printed on to view changes in slope] better. For small changes in an underlying trend, similar to that apparently shown in the comic, direct visual inspection cannot always identify or even reveal the effect. The comic shows, however, that by taking the page and rotating it in just the right way, the foreshortened perspective can make certain details much more apparent, allowing the 'expert' to see at a glance that there is a change in the slope. Ironically, tilting the comic to make the original roughly resemble the perspective of the 'tilted' version graph shown in the comic shows that the right-hand panel is slightly exaggerated for visual effect. The use of {{w|Perspective (graphical)|perspective}} to make information pop into the audience's view has been used by artists for {{w|The_Ambassadors_(Holbein)|centuries}}.

However, applying such an approach to data plots can run into errors — the primary one being parallax error from the oblique viewing angle causing the observer to not necessarily identify or clearly find the point at which the slope changes. It also does not reveal any data about the quantitative value of the change in slope, merely proving the existence of one. Furthermore, noisy data might show an apparent slope change that is not representative of an actual change in the underlying data, so even more advanced [https://www.danielsoper.com/statcalc/calculator.aspx?id=103 statistics testing the hypothesis of whether an apparent slope change is real] may likely be a good idea.

The title text then goes on to say that, while such a trick is useful to identify that there is some change in slope, in order to ''pretend'' to know it exactly one must revert to statistics (the "novice method") to obtain some form of information, defeating some of the premise of the comic. This at least produces a semblance of statistical rigor although, once an answer appears obvious, data could be interpreted to reach an answer that you are now expecting rather than revealing something of more statistically useful significance.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:How to detect a change in the slope of your data

:[First column, on the left]
:Novice method:
:[A graph, with dots forming a rough line, math formulas, and sub graphs]
:Do a bunch of statistics

:[Second column, on the right]
:Expert method:
:[Perspective view of the previous graph, with the legend "Hey look, it bends here" and an arrow pointing to the graph]
:Tip the graph sideways

{{comic discussion}}

[[Category:Charts]]
[[Category:Scatter plots]]
[[Category:Bar charts]]
[[Category:Line graphs]]
[[Category:Statistics]]

2668: Artemis Quote

2022-09-05T22:51:42Z

172.69.34.44: /* Explanation */ redundant

{{comic
| number = 2668
| date = September 5, 2022
| title = Artemis Quote
| image = artemis_quote.png
| titletext = Another option: "It is an honor to be the first human to set foot on the moon."
}}

==Explanation==
{{incomplete|created by a WOMAN INHERITS THE EARTH. Do NOT delete this tag too soon.}}

The {{w|Artemis program}} is a series of planned space missions that will land humans on the moon and begin to set up infrastructure for a permanent human presence. Humans first landed on the moon in 1969 as part of the Apollo program. They have not been back since 1972.

When the first human to walk on the moon, {{w|Neil Armstrong}}, took the first step there, he was intending to say, "That's one small step for '''a''' man, but a giant leap for mankind" [emphasis added]. The audio recording omits the first instance of the word "a", making the sentence confusing and self-contradictory as the group refered to as "mankind" can also typically be described as "man" which leaves the "but" as a comparison between the same thing simultaneously doing two contradictory things.

This recording was broadcast worldwide at the time and has become a famous historical quote. However, that the {{w|schwa}} grammatical article, "a", optional in certain contexts of most dialects of American English,{{Actual citation needed}} was apparently elided by Armstrong in the excitement, modifying the semantic meaning of the historical phrase, is controversial and therefore funny. Subsequently Armstrong and others have blamed insufficiently tuned {{w|voice activity detection}} hardware circuitry intended to save power in radio voice transmission, but NASA engineers, third-party historians and their hired experts have never been able to corroborate that excuse.

Randall proposes that the first Artemis astronaut should create an even more confusing quote by proposing a sentence that actually appears to be a mere reference to whatever it is they have said. Speaking as if they are alluding to something from the past, it would add contextual confusion to any attempt to directly quote or replay the words from then on. This is very unlikely, and funny merely as a recommendation. If it actually happened, it might be both hilarious and scandalous.

The title text suggests an alternate phrase by which the Artemis astronaut would claim to be the first (rather than 13th) human on the moon. People hearing this quote in the future could assume that Artemis was the first manned mission to the Moon.  It may also have been intended as a phrase Armstrong could have used with less chance of flubbing, but seems inappropriately self-aggrandizing for the mild-mannered astronaut and makes no sense to be declaimed by Artemis's pioneering moonwalker.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:[The surface of the moon, with craters and rocks, and a rocket with a ladder attached and an astronaut stepping onto the moon's surface.]
:Astronaut: This is one of my favorite historical quotes -- the first words spoken by an Artemis astronaut on the moon.

:Caption: Neil Armstrong's "man"/"a man" quote created a lot of historical confusion, and I think it's our duty to expand on that legacy with Artemis.

{{comic discussion}}

2668: Artemis Quote

2022-09-05T22:49:13Z

172.69.34.44: /* Explanation */ restore neglected edit conflict clobber

{{comic
| number = 2668
| date = September 5, 2022
| title = Artemis Quote
| image = artemis_quote.png
| titletext = Another option: "It is an honor to be the first human to set foot on the moon."
}}

==Explanation==
{{incomplete|created by a WOMAN INHERITS THE EARTH. Do NOT delete this tag too soon.}}

The {{w|Artemis program}} is a series of planned space missions that will land humans on the moon and begin to set up infrastructure for a permanent human presence. Humans first landed on the moon in 1969 as part of the Apollo program. They have not been back since 1972.

When the first human to walk on the moon, {{w|Neil Armstrong}}, took the first step there, he was intending to say, "That's one small step for '''a''' man, but a giant leap for mankind" [emphasis added]. The audio recording omits the first instance of the word "a", making the sentence confusing. This recording was broadcast worldwide at the time and has become a famous historical quote. However, that the {{w|schwa}} grammatical article, "a", optional in certain contexts of most dialects of American English,{{Actual citation needed}} was apparently elided by Armstrong in the excitement, modifying the semantic meaning of the historical phrase, is controversial and therefore funny. Subsequently Armstrong and others have blamed insufficiently tuned {{w|voice activity detection}} hardware circuitry intended to save power in radio voice transmission, but NASA engineers, third-party historians and their hired experts have never been able to corroborate that excuse.

Randall proposes that the first Artemis astronaut should create an even more confusing quote by proposing a sentence that actually appears to be a mere reference to whatever it is they have said. Speaking as if they are alluding to something from the past, it would add contextual confusion to any attempt to directly quote or replay the words from then on. This is very unlikely, and funny merely as a recommendation. If it actually happened, it might be both hilarious and scandalous.

The title text suggests an alternate phrase by which the Artemis astronaut would claim to be the first (rather than 13th) human on the moon. People hearing this quote in the future could assume that Artemis was the first manned mission to the Moon.  It may also have been intended as a phrase Armstrong could have previously used with less chance of flubbing, but seems inappropriately self-aggrandizing for the mild-mannered astronaut and makes no sense to be declaimed by Artemis's pioneering moonwalker.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:[The surface of the moon, with craters and rocks, and a rocket with a ladder attached and an astronaut stepping onto the moon's surface.]
:Astronaut: This is one of my favorite historical quotes -- the first words spoken by an Artemis astronaut on the moon.

:Caption: Neil Armstrong's "man"/"a man" quote created a lot of historical confusion, and I think it's our duty to expand on that legacy with Artemis.

{{comic discussion}}

2667: First Internet Interaction

2022-09-05T17:31:40Z

172.69.34.44: /* Transcript */ music

{{comic
| number = 2667
| date = September 2, 2022
| title = First Internet Interaction
| image = first_internet_interaction.png
| titletext = To that stranger on the KOOL Tree House chat room, I gotta hand it to you: You were, ultimately, not wrong.
}}

==Explanation==
{{incomplete|Created by AN AMERICAN IDIOT - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

In this comic, [[Cueball]], very likely as an autobiographical representation of [[Randall]], describes to [[Megan]] the first time he interacted with a group of people unknown to him over the internet; in an {{w|AOL|AOL}} chat room for children called the "KOOL Tree House chat room" in 1993, when Randall was about nine years old. He read a discussion about {{w|Green Day}}, asked who they are, and was told that not knowing was a serious problem. As Megan says, judging people for lack of pop culture knowledge has remained typical online behavior.

Green Day is an American rock band formed in the East Bay of California in 1987. In 1993, they were still known merely as an independent punk band, and a year away from releasing their major-label debut album ''{{w|Dookie}}'', their first mainstream success. Anyone, especially a nine year-old, not recognizing the band in 1993 would be perfectly normal. After 1993, Green Day would go on to be a widely popular and influential rock band with many acclaimed albums.

This initial online social interaction was a significant formative experience for Cueball, molding his online behavior ever since, in that it still causes him to consider his correspondents' perspectives when communicating. The social dynamics at play are reminiscent of the mathematics of others' perspectives described in [[1053: Ten Thousand]]. Relating the personal experience of an oversized effect from a casual insult is humorous because the extent to which early experiences affect people can be both ironic and profound.

The title text indicates Cueball agrees with the reply to the question. This is humorous because it is effectively Cueball admitting that something is very wrong with him, possibly coincidental with and unrelated to knowing that specific piece of trivia. Alternatively, Cueball could have come to believe Green Day is culturally important. If this story is autobiographical, Randall could have hence become a Green Day fan, or at least acquired more than a passing knowledge of their {{w|œuvre}}, recently mentioning their song "{{w|American Idiot (song)|American Idiot}}" in [[2665: America Songs]].

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[First panel, Megan and Cueball talking]
:Cueball: You know,
:Cueball: I remember the first thing anybody ever said to me on the internet.
:Megan: Yeah?

:[Second panel, part-height to accomodate Cueball's narration above and the memory of a scene below that features 'Young Cueball', with a mop-head of hair, knelt atop a chair to use a computer with CRT and keyboard on the desk, cabled down into a floor-standing minitower case below]
:Cueball (narrative): I was in an AOL Kids chat room in 1993.
:Cueball (narrative): People there kept using a name I didn't recognise.
:Cueball (narrative): After a while I asked what it was.
:Young Cueball (via the use of the keyboard): W... H... O...  I... S...  G... R...

:[Third panel, close-up of Cueball's adult head, continuing the framing conversation]
:Cueball: Someone replied.
:Cueball: "If you don't know who Green Day is, you have a serious problem."
:Cueball: And that was it. My first virtual interaction.

:[Fourth panel, continuing the conversation, Megan and Cueball now seen walking rightwards as they speak]
:Megan: In some ways, the Internet has changed surprisingly little in the last 30 years.
:Cueball: Every time I reply to someone, I think
:Cueball: What if this is their Green Day moment?

{{comic discussion}}
[[Category:Comics featuring Cueball]] 


[[Category:Comics featuring Megan]]
[[Category:Comics featuring Randall Munroe]] 
[[Category:Music]]

2643: Cosmologist Gift

2022-07-09T01:50:23Z

172.69.34.44: /* Explanation */ fix per talk

{{comic
| number = 2643
| date = July 8, 2022
| title = Cosmologist Gift
| image = cosmologist_gift.png
| titletext = These neutrinos were freshly produced by a local source just 8 minutes ago
}}

==Explanation==
{{incomplete|Created by a MUON ON SALE- Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This comic shows a box labeled to indicate that it contains 30,000 fresh {{w|neutrino}}s and four zeptograms of {{w|dark matter}}. The box is intended as an inexpensive gift for a {{w|cosmologist}}. The gift giver didn't put those things in the box; both are simply passing through it. While the caption states that this would be a good gift for a cosmologist, what they or anyone else would do with such a box is uncertain.

There are about a billion neutrinos per cubic meter throughout space, produced during the {{w|Big Bang}}.[https://physics.mit.edu/news/journal/physicsatmit_14_conrad/] However, the flux of "freshly produced" {{w|solar neutrino}}s at Earth is around 7×1010/cm2/s, yielding about 23,000 per cubic meter.

Four zeptograms is a minuscule mass, equal to four sextillionths of a gram, or the mass of about 200 carbon-12 atoms. There is an estimated 0.011 to 0.016 {{w|solar mass}}es of dark matter per cubic {{w|parsec}} locally to the solar system,[https://iopscience.iop.org/article/10.1088/1361-6633/ac24e7/meta] or about 900 zeptograms per cubic meter. This discrepancy with the number of solar neutrinos in the box suggests Randall might agree with the cosmologists who believe that dark matter is at least partially composed of black holes,[https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.120.121301][https://www.sciencedirect.com/science/article/abs/pii/S2212686418301250?via%3Dihub][https://news.yale.edu/2021/12/16/black-holes-and-dark-matter-are-they-one-and-same][https://iopscience.iop.org/article/10.3847/2041-8205/823/2/L25][https://iopscience.iop.org/article/10.1088/1475-7516/2010/04/023] instead of being entirely composed of pervasive subatomic particles.

The "local source" mentioned in the title text is the Sun; it takes light and neutrinos 8 minutes to reach Earth once they're emitted.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:[A picture of a box with writing on one side, saying as follows:]

:30,000 neutrinos
:Freshly produced
:Plus 4 zeptograms of dark matter

:[Caption below the panel]:
:Cosmologists are easy to shop for because you can just get them a box.

{{comic discussion}}
[[Category:Astronomy]]

Talk:2335: Photo Deposit

2020-07-22T22:34:45Z

172.69.34.44:

Depositing cash through a smartphone app was one of the silliest and most useful features in GTA V. Unfortunately, depositing money would not duplicate it. Presumably the characters in the game are very honest and trustworthy, destroying any cash instantly after scanning it in. This honesty is to be expected from thieving killers such as these.

You can also withdraw cash via the app. How that works is beyond me.

--[[User:NeatNit|NeatNit]] ([[User talk:NeatNit|talk]]) 23:38, 20 July 2020 (UTC)

A frequent joke in "The Goon Show" on 1950s British radio was the offer of a printed photograph of usually a small sum of money, treated as the photograph actually having value itself. Sometimes it's a phonograph disc. And sometimes the money represented turns out to be a forgery. In a less silly context, the photograph might be considered as an I.O.U., as evidence that the money exists and will be paid... which is what a banknote is, really. But in practice someone influencing you with pictures of money might be dishonest. Bank advertising for instance.

Wikipedia's article on "The Goon Show running jokes" (!) doesn't mention money photographs, although there is a reference to handing out pictures of Queen Victoria, especially in historical stories. Pictures of Queen Victoria may be on older money, but these ones don't seem to be.

Robert Carnegie rja.carnegie@excite.com [[Special:Contributions/141.101.98.26|141.101.98.26]] 08:18, 21 July 2020 (UTC)
: Search for "photo"(graph) in http://www.thegoonshow.net/scripts_show.asp?title=s06e07_foiled_by_president_fred for the instant(s) that came straight to my mind, being recently broadcast. (I assume you're familiar with LSD?) [[Special:Contributions/162.158.159.14|162.158.159.14]] 09:38, 21 July 2020 (UTC)

"Other nations ... have started introducing plastic banknotes" Lol. Australia had *finished* introducing plastic bank notes 30 years ago. [https://csiropedia.csiro.au/polymer-banknotes/] [[User:Boatster|Boatster]] ([[User talk:Boatster|talk]]) 01:43, 21 July 2020 (UTC)

Hmm. How much money would that be? Say each photo is 4MB and your upload speed is 25 or so Mb/s. Each upload would take about 1.3 secs. We'll round up to 1.5. To keep it simple, we'll say that they have a stack of bills, and are able to scan each new bill within those 1.5 seconds. Now, if the bank allows you to upload $100 bills, without any rate limiting, you'd be able to make $400/min (the same as the what if article, weird). Which means that in six hours, they could make $144,000 dollars! Of course, this is mostly guesswork, but it should be somewhere in the ballpark.
Could be a little more: Smaller photos, better network.
Or a lot less: Most people don't have $144,000 in cash ready at a moment's notice, and scanning could take more than 1.5 secs.
Of course, if this was a feature that was announced, and they had time to prepare....
[[Special:Contributions/108.162.245.102|108.162.245.102]] 04:11, 21 July 2020 (UTC)
: $100*(60/1.5)sec = $4000 per min, or $1.44 million in 6 hours. You forgot that there are 2 phones, so double that. Also, you wouldn't need ALL the money, you (or an assistant) can take the money already scanned to another bank and swap it for new cash, repeat. [[Special:Contributions/162.158.123.173|162.158.123.173]] 17:57, 22 July 2020 (UTC)

The feature of depositing check is this new or old... Is it something from before or after the Corona outbreak? It is a smart feature to avoid visits to banks during the pandemic - also the money thing, which of course is not realistic irl. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 09:19, 21 July 2020 (UTC)
:depositing checks by smartphone is old, going back to 2018 if not earlier, and the depositing of currency could be realistic if bills used blockchain ledger entries instead of easily guessed serial numbers and everyone verified every currency transaction against the blockchain every time (this would end counterfeiting as a side effect). [[Special:Contributions/162.158.63.172|162.158.63.172]] 09:53, 21 July 2020 (UTC)
::Yes but that entirely defeats the purpose of cash, if you have to verify every transaction against a database. Also blockchain is entirely unnecessary. [[User:Probably not Douglas Hofstadter|Probably not Douglas Hofstadter]] ([[User talk:Probably not Douglas Hofstadter|talk]]) 06:11, 22 July 2020 (UTC)
:The Chase app started allowing deposits ten years ago. See this article from ten years ago today: https://phys.org/news/2010-07-banking-deposit-smart-phone-photo.html [[User:Orion205|Orion205]] ([[User talk:Orion205|talk]]) 03:44, 22 July 2020 (UTC)

Is it by the way illegal to even take a picture of banknote? I know printing one out is... Even if only one side and not very good quality. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 09:27, 21 July 2020 (UTC)
:if taking pictures of banknotes is illegal then bank security cameras (and security cameras in many retail establishments and casinos) are routinely breaking the law. Also, aren’t change machines taking a picture as part of their anti-counterfeiting circuits? [[Special:Contributions/162.158.63.172|162.158.63.172]] 09:58, 21 July 2020 (UTC)
::Even printing banknote is legal if you follow some rules. I read that you need to make it bigger than 150% or smaller than 75% of real size, although details may vary depending on country. Of course, doesn't change the fact that your graphics program might refuse to work with that image and your printer may refuse to print it. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 23:39, 21 July 2020 (UTC)

I know it's acceptable in the 'colonial' idiom, but seeing "cheques" spelt as "checks" always confuses me for a micromoment. As well as imagining a test/verification being somehow a bartered service, I'm only just getting past it also being a bill-of-fare (in the UK we may pay a bill with a cheque, over there you can pay a check with a bill). But carry on carrying on! I'll get my coat. (If I can find the coat-check.) [[Special:Contributions/162.158.159.100|162.158.159.100]] 10:01, 21 July 2020 (UTC)
:Yes, we need to spell it as "chex" [[Special:Contributions/162.158.123.173|162.158.123.173]] 17:46, 22 July 2020 (UTC)

Why is cryptocurrency in there, it seems tangential at best? [[User:Djbrasier|Djbrasier]] ([[User talk:Djbrasier|talk]]) 19:01, 21 July 2020 (UTC)
:The more paranoid (or stand-offish for their own good reasons) Crypto users might not even connect bitwallets electronically but pass a transaction-code by other means (retyped from hardcopy, or rescan an on-screen generated QR, depending on requirements) and then rely upon the decentralised 'audit book' checking and authorising that transaction with minimal{{Citation needed}} risk of subsequent tracing-and-linking-together by The Man/whoever. I think it's both far too paranoid ''and'' not paranoid enough, in equal measure, if you're trying to keep your associations off-grid, but it seems there are those who seem to like doing it that way. [[Special:Contributions/141.101.98.222|141.101.98.222]] 20:35, 21 July 2020 (UTC)

The explanation seems excessive, given how obvious the joke is. [[User:Gvanrossum|Gvanrossum]] ([[User talk:Gvanrossum|talk]]) 04:58, 22 July 2020 (UTC)

Curse my memory over ~10-15years! I vaguely remember a traveler focused bank that accepted cash deposits. They'd add the amount to your account, you could spend it and they'd cover the costs, and if you didn't have the bills submitted to one of their locations across the globe within a certain amount of time they'd rip you a new one in fees. The photos had to be perfect, and even then they were up for review and could be rejected by a human who didn't like the background it was sitting on. I remember my parents only ever used it once and needed my help understanding it so it was just right. [[Special:Contributions/108.162.216.34|108.162.216.34]] 18:50, 22 July 2020 (UTC)

This reminds me of that time Domino's allowed you to earn points to a free pizza by taking pictures of pizza. [[Special:Contributions/172.69.34.44|172.69.34.44]] 22:34, 22 July 2020 (UTC)

2293: RIP John Conway

2020-04-15T17:13:19Z

172.69.34.44: /* Explanation */ CA

{{comic
| number = 2293
| date = April 13, 2020
| title = RIP John Conway
| image = rip_john_conway.gif
| titletext = 1937-2020
}}

==Explanation==
{{incomplete|Created by a GLIDER. Needs more in-depth explanation of how the Game Evolves. Include remaining stills from the GIF in the table below. Should also expand more on why Conway is a person of note. Do NOT delete this tag too soon.}}

{{w|John Horton Conway|John Conway}}, an English mathematician, passed away of COVID-19 on April 11, 2020. Two days later, [[Randall]] created this [[:Category:Tribute|memorial comic]]. It is the 6th memorial comic, but it is the first released in almost 5 years, since [[1560: Bubblegum]].

One of Conway's most famous creations was the {{w|cellular automaton}} known as {{w|Conway's Game of Life}}. A cellular automaton is a machine composed of cells, each of which can be in a different state. Every generation, each cell in the automaton may transition to a new state depending on a set of rules. (Conway's work in mathematics was vast and various, but he is perhaps best known in the field for discovering the {{w|surreal numbers}}, which inspired Donald Knuth to write a novel which may have been referenced back in [[505: A Bunch of Rocks]].)

Conway's Game of Life is a 2-state automaton (i.e., every cell can be "alive" or "dead") that is implemented on a two-dimensional grid of cells using the {{w|Moore neighborhood}} - this means that each cell can only be influenced by the eight cells directly surrounding it, both orthogonally and diagonally. The transition rules that Conway discovered are as follows:

* If an "alive" cell has no live neighbors, or only one live neighbor, it becomes "dead". (This simulates death by isolation).
* If an "alive" cell has four or more live neighbors, it becomes "dead". (This simulates death by overcrowding).
* If a "dead" cell has exactly three live neighbors, it becomes "alive". (This simulates birth).

Despite the simplicity of these three rules, Conway showed that patterns of amazing complexity can nonetheless develop out of simple cell arrangements. Some patterns do not evolve at all ("still lifes"), some enter a cyclic, repeating state ("oscillators"), and some reproduce their own pattern displaced by an offset, resulting in patterns that can move across the grid under their own power ("gliders" and "spaceships"). This last category is of particular interest, as it allows the Game of Life to transmit information from one location to another, allowing for rich, dynamic behavior and even for the creation of computational machines within the automaton itself.

This comic begins with the shape of a stick figure as the starting cell configuration of the Game of Life. The black cells are "alive" and the white cells are "dead". This configuration then evolves via Conway's rules, disintegrating into nothingness except for a five-cell pattern known as a "glider", which ascends up and to the right. This visually suggests a "soul" breaking away from the disintegrating corporeal body. The glider is perhaps the most iconic pattern of the Game of Life, and is often used symbolically to represent the phenomenon of emergence.

The initial state presented in the comic does actually evolve in that manner, as can be verified by entering the pattern into a cellular automaton simulator such as [http://golly.sourceforge.net/ Golly] or web services such as [https://bitstorm.org/gameoflife/ this one].

The title text simply states Conway's birth and death year: 1937-2020.

Conway's Game of Life was previously mentioned in [[696: Strip Games]]. Cellular automata was also referenced in [[505: A Bunch of Rocks]].

This comic may be the 18th comic in a row (not counting the [[2288: Collector's Edition|April Fools' comic]]) in a [[:Category:COVID-19|series of comics]] related to the {{w|2019–20 coronavirus outbreak|2020 pandemic}} of the {{w|coronavirus}} {{w|SARS-CoV-2}}, which causes {{w|COVID-19}}.

==Table of generations==
{| class="wikitable"
!Generation
!Notes
|-
|[[File:Generation 0.jpg|thumb]]||Starting state (or "zeroth generation").
|-
|[[File:Generation 1.jpg|thumb]]||First generation. Note that this image is not aligned with the previous one: the position of all cells has shifted downward by one cell. All further generations are aligned the same as this one.
|-
|[[File:Generation 2.jpg|thumb]]||Second generation.
|-
|[[File:Generation 3.jpg|thumb]]||Third generation.
|-
|[[File:Generation 4.jpg|thumb]]||Fourth generation.
|-
|[[File:Generation 5.jpg|thumb]]||Fifth generation.
|-
|[[File:Generation 6.jpg|thumb]]||Sixth generation. The first appearance of the glider, a well-known formation in Conway's Game of Life.
|-
|[[File:Generation 7.jpg|thumb]]||Seventh generation. The glider takes on its other shape.
|-
|[[File:Generation 8.jpg|thumb]]||Eighth generation. The glider returns to its first shape, pointing right instead of up.
|-
|[[File:Generation 9.jpg|thumb]]||Ninth generation. The glider's second shape again, pointing right instead of up.
|-
|[[File:Generation 10.jpg|thumb]]||Tenth generation. The glider is now in its original form, but one cell higher and one cell to the right. It will continue to progress, cycling through these four states every four generations. The remains of the chaos down below will take two more generations to disappear completely.
|}

==Transcript==
:[A pixelated image of a stick figure using 21 pixels, could be a pixel Cueball, which waves with one hand up while holding the other hand down. The head consist of 7 pixels, the top row of three having two pixels beneath the two outer pixels, thus having two empty pixels beneath the central pixel. The neck and torso is a typical cross made from six pixels. The two legs are two pixels each shifted left and right of the cross. The arm to the left that waves is two pixels one down and the next back up to the level of the cross central beam. The arm to the right has the first pixel similarly but the second pixel continues one further step down. After less than one second it turns out that the image is animated, with the pixels changing according to the rules of Conway's Game of Life. The figure splits into three groups, two of which dissipates in a similar way at the bottom of the panel. The other becomes a 'glider' and moves off to the top-right corner of the image and out of the frame. The animation then repeats.]

{{comic discussion}}

[[Category:Tribute]]
[[Category:COVID-19]]
[[Category:Comics with animation]]
[[Category:Comics featuring real people]]

Talk:2293: RIP John Conway

2020-04-15T17:10:13Z

172.69.34.44: edit, previously referenced

This is really very impressive. The design of the stick figure to allow it to release a glider that ascends upwards (the "soul" rising to "heaven" or whatever) with the body decaying - that's a hard thing to get right using just the Game of Life rules. [[Special:Contributions/172.69.68.175|172.69.68.175]] 17:49, 13 April 2020 (UTC)
:Although Randall is clever, the Game of Life has been studied for so long that I'm sure this is a well-known animation. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 18:29, 13 April 2020 (UTC)
:: I played with the game a bunch in the past, but I've only done a bit of research after this appeared. I don't immediately find any previous report of this starting arrangement
:: This is unlikely, as the Game of Life has an uncountable number of patterns of this size, some of which are still being discovered. The pattern above is 7 cells wide by 9 cells tall - the number of distinct patterns that can be drawn in that box nears 2 --> 60 --> 1 (2^60). It's most likely that patterns such as this one are commonplace, and Randall just fiddled around until he reached one that he desired. The pattern itself, however, has likely never been discovered before. (As a fun postscript, [http://catagolue.appspot.com/object/xp16_0c2w3vz33032988/b3s23 a notable 8-cell wide, 9-cell tall pattern oscillating at period 16], just slightly larger than the one above, was discovered in February 2020.)[[User:Hdjensofjfnen|Hdjensofjfnen]] ([[User talk:Hdjensofjfnen|talk]]) 21:31, 13 April 2020 (UTC)
:::I suspect it's probably more likely that he worked it out backwards, rather than "just fiddled with it." [[Special:Contributions/108.162.216.244|108.162.216.244]] 04:24, 14 April 2020 (UTC)
::::AFAIK, many CAs such as Life have the property of being irreversible, which is the entire point for various pattern search efforts.[[Special:Contributions/162.158.92.54|162.158.92.54]] 07:13, 14 April 2020 (UTC)
:::::He probably started with the floater, and adjusted the rest so it wouldn't interfere. Most figures decay in the game of life (I learned when playing with it, decades ago) --[[Special:Contributions/162.158.111.79|162.158.111.79]] 10:45, 14 April 2020 (UTC)
:::::The Game of Life has been researched a lot. One sub-problem is finding an arrangement of cells that cannot be produced by a prior arrangement of cells. They are called Garden of Eden patterns, and the known ones are not small. Glider generators are rather common, so it is most likely that the initial pattern was created by working backward from an existing glider generator.[[Special:Contributions/173.245.54.125|173.245.54.125]] 17:33, 14 April 2020 (UTC)

was there a placeholder comic posted before the gif went live?

:I am certain there was one with "uh oh one of the lights went out" "that's not supposed to happen" and a picture of a pattern that I did not recognise, which I found to be quite sad. [[Special:Contributions/162.158.92.54|162.158.92.54]] 10:35, 14 April 2020 (UTC)

::This was SMBC, and the pattern is a glider generator. [[Special:Contributions/188.114.111.211|188.114.111.211]] 12:30, 14 April 2020 (UTC)

Looks like this is second animated comic in xkcd, besides 1116(though 1190 could be possibly counted together) [[Special:Contributions/172.69.190.16|172.69.190.16]] 19:34, 13 April 2020 (UTC)
:Uh, [[1331: Frequency]] and [[1264: Slideshow]] immediately come to mind, and then I remember about [[961: Eternal Flame]]. There's a lot more than two. [[User:Volleo6144|Volleo6144]] ([[User talk:Volleo6144|talk]]) 19:43, 13 April 2020 (UTC)
::[[:Category:Comics with animation]]; just added it. [[User:Yngvadottir|Yngvadottir]] ([[User talk:Yngvadottir|talk]]) 20:19, 13 April 2020 (UTC)

The explanation says that the simulation is run on an infinite grid, but even when the grid is calculated out beyond the border of the viewable area, bounding errors & boundary formations can occur. I've never seen ''any'' implementation that actually produces an infinite, nor even ''practically'' infinite grid. (In fact, wasn't there a Minecraft mod that runs until it lags out the engine?) Can anybody point me to a truly infinite grid implementation? Conway's ''definitely'' was not infinite, he even commented at length about the boundary formations that show up at the grid edges (which are among the most subjectively beautiful, incidentally). I think the explanation needs correction?
[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 21:59, 13 April 2020 (UTC)
: The explanation is describing Conway's game of life, not any particular implementation IMHO. No change needed IMHOA. Also, the previous post was not signed properly. [[Special:Contributions/162.158.107.167|162.158.107.167]] 21:47, 13 April 2020 (UTC)
::Except many of Conway's observations about the "game" & even ''his initial description'' of it explicitly state & indeed hinge upon the fact that it's not (& thus far ''cannot'' be) implemented as an "infinite" grid. Part of the whole point of his experiment with it & the various demonstrations is to illustrate edge effects resulting from a finite range of calculations. '''It's extremely relevant that it's''' '''''not''''' '''infinite.''' It's actually kinda the whole point of his creating it, much the same way people working with fractals likewise tend to become very interested in bounding errors. The boundaries are where the interesting work is done. Apparently someone agreed with me at least in part, because they edited the wording. Thanks... Brian? I think we should actually '''add''' to the description of the "game" info highlighting the edge effects, because that's the primary focus of the project & its outgrowths in the first place. (We can't adequately simulate infinity & that's a big part of the interest in it.) Also, I frequently have to submit & then refresh & sign afterward because of the device I'm on. In this case I'm glad I did, because I saw your reply & the other new stuff!
::[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 22:17, 13 April 2020 (UTC)
:Golly uses a grid of arbitrary size by default. It can very easily be verified to at least ±210000. (Note that it also includes finite rectangular and toroidal grids.) [[User:LegionMammal978|LegionMammal978]] ([[User talk:LegionMammal978|talk]]) 01:39, 14 April 2020 (UTC)
No computer [Citation Needed] can run an ''actual'' infinite grid, but with some intelligent bounding you can mitigate early signs of problems by maintaining "bubbles" of cells with offsets. You get into problems once you start machine-gunning out gliders (offsets will eventually overflow or awkwardly lose precision, depending on the var-types used; and maintaining a longer and longer bubble, or more and more bubbles just above glider-sized, is probably your other challenge) but it's probably good enough for most purposes. If you somehow have finite patterns that move out in huge (wasteless) cycles from the 'origin' and hold that path until enacting hugely-delayed doglegs (mathematically, it must be a point no further away than can be reasonably enumerated by the bits of information contained within each formation, and significantly less as it'd be a far less efficient count-down cycler than any folded LFSR, but it's ''imaginable'') to meet again at some arbitrary (though deterministic and replicable) distance out in the far far reaches of your abstracted bubble-land then it's possible you could ''pretend'' you have infinite space. [[Special:Contributions/162.158.91.101|162.158.91.101]] 22:26, 13 April 2020 (UTC)

[[User:ProphetZarquon|ProphetZarquon]], do you have a source for your claim that the main point of Conway's creation of Life was to study the edge effects? [https://conwaylife.com/wiki/Conway%27s_Game_of_Life The page for Life on its own wiki] describes the Life grid as "infinite" and only mentions edge effects as inaccuracies to be avoided, and [https://www.youtube.com/watch?v=R9Plq-D1gEk this Conway interview about Life's creation] doesn't mention edges at all.
[[Special:Contributions/108.162.241.24|108.162.241.24]] 23:34, 13 April 2020‎ (UTC)
:First of all, as a tip, reply directly to the comment when you want to talk with someone. Secondly, yeah, I'm pretty sure that person's just blasting ass ham. [[Special:Contributions/172.69.69.28|172.69.69.28]] 02:49, 14 April 2020 (UTC)

Possibly worth noting is the bit of artistry in the rendering. Munroe alters the step period of the iterations so that the deconstruction of the humanoid shape happens more quickly, with the stepping of the glider translating away occurring more slowly. [[User:Fixer|Fixer]] ([[User talk:Fixer|talk]]) 21:52, 13 April 2020 (UTC)

I like the comic very much, and I'm afraid to say I hadn't heard of his death in amongst... well, everything else. RIP.
While I'm here, though, I'm a bit concerned about the current cell generation cycle explanation, as it feels awkward. Currently it is (paraphrased) "live cells survive if just enough neighbours / dead cells come to life with exactly enough neighbours / any other dies or stays dead". I'd prefer something that more delineates it as birth (dead to live, by propogation from the right number of live neighbours), death (live to dead due to ''either'' isolation ''or'' overcrowding) and continuation of state in all other cases. Can't work out a good phrasing yet, but ''may'' try it out later. [[Special:Contributions/162.158.91.101|162.158.91.101]] 22:26, 13 April 2020 (UTC)
: Agreed 100%. I believe the problem lies in the confusion between "cell as in biology" versus "cell as in jail". It would be better to avoid the word "cell" and describe a grid with squares that are either inhabited or empty; inhabitants with two or three neighbours survive to the next generation, otherwise they die (square becomes empty the next generation); exactly three neighbours to an empty square will give birth (become inhabited) in the next generation; and any other empty square stays empty.

Given the cause of death, should this comic be listed among the Covid-19 series? [[User:Momerath|Momerath]] ([[User talk:Momerath|talk]]) 05:02, 14 April 2020 (UTC)
:Yes.--[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 10:51, 14 April 2020 (UTC)
:No. This is about John Conway. It would have presumably run regardless of the cause of death.

Interesting to see if the next comic is also a Covid-19 comic, because then it will be the 19th covid-19 comic... --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 10:53, 14 April 2020 (UTC)

I really think this should not be regarded as a Covid-19 comic, since it's a memorial one and the cause of death is not important for this comic. [[Special:Contributions/162.158.93.105|162.158.93.105]] 14:18, 14 April 2020 (UTC)
:Agree with the others, this is a memorial comic, NOT a COVID-19 comic. I feel like too many comics are being forced into the COVID-19 theme, when they have little to no relation. [[Special:Contributions/172.69.22.62|172.69.22.62]] 16:12, 14 April 2020 (UTC)
::Covid-19 is obviously not directly the topic of the comic, but it is related quite close. So I vote to re-add it to the category, but to put the mention of the connection with the other comics not into the explanation, or on its bottom. If this is acceptable, [[961: Eternal Flame]] should also be included to [[:Category:Cancer]]. --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 10:43, 15 April 2020 (UTC)
:::Of course this is one in the Covid series. Randall very rarely makes tributes and it has been 5 year since the last. Conway is not very famous, and had he died a year ago, chances are Randall would not have made this comic. But because he died of Covid while all Randall's comics is about Covid he makes a tribute now. For the same reason I do not think that Eternal flame has anything with the cancer category. Because this was a tribute Randall made without any connection to a series of cancer comics. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 11:25, 15 April 2020 (UTC)
::::Thanks for correcting my spelling errors :D all of that is speculation. How do you know, that Randall is not a huge Conway fan? seems to play exactly into his geekynes. --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 12:47, 15 April 2020 (UTC)
:::::I also disagree that Randall is not a huge Conway fan. I believe he would be familiar and interested in the Game of Life automata, as a nerd/geek. It was previously mentioned over 10 years ago in [[696: Strip Games]]. I agree with Lupo's suggestions for this comic. [[Special:Contributions/172.69.34.44|172.69.34.44]] 17:01, 15 April 2020 (UTC)

== Is this original? ==

It would seem remarkable if Randall was able to create this starting pattern at such short notice. If it's copied from somewhere, we should provide that detail. [[User:Stevage|Stevage]] ([[User talk:Stevage|talk]]) 03:54, 15 April 2020 (UTC)
:I do not know if it is taken from another place or a common/known pattern (the comments above seem to suggest otherwise), but it is not uncommon to have an obituary / memorial in stock for elderly persons of relevance. So it might be possible, that e.g. Randall played around with putting stick figures into a simulation, and accidently found this, deciding to keep it somewehere in his archive for this occasion. The seperation of the decaying body and the everlasting part going upward is actually obvious enough to connect with the idea to use it for this occasion. --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 10:36, 15 April 2020 (UTC)

2293: RIP John Conway

2020-04-15T17:08:33Z

172.69.34.44: /* Explanation */ previously mentioned

{{comic
| number = 2293
| date = April 13, 2020
| title = RIP John Conway
| image = rip_john_conway.gif
| titletext = 1937-2020
}}

==Explanation==
{{incomplete|Created by a GLIDER. Needs more in-depth explanation of how the Game Evolves. Include remaining stills from the GIF in the table below. Should also expand more on why Conway is a person of note. Do NOT delete this tag too soon.}}

{{w|John Horton Conway|John Conway}}, an English mathematician, passed away of COVID-19 on April 11, 2020. Two days later, [[Randall]] created this [[:Category:Tribute|memorial comic]]. It is the 6th memorial comic, but it is the first released in almost 5 years, since [[1560: Bubblegum]].

One of Conway's most famous creations was the {{w|cellular automaton}} known as {{w|Conway's Game of Life}}. A cellular automaton is a machine composed of cells, each of which can be in a different state. Every generation, each cell in the automaton may transition to a new state depending on a set of rules. (Conway's work in mathematics was vast and various, but he is perhaps best known in the field for discovering the {{w|surreal numbers}}, which inspired Donald Knuth to write a novel which may have been referenced back in [[505: A Bunch of Rocks]].)

Conway's Game of Life is a 2-state automaton (i.e., every cell can be "alive" or "dead") that is implemented on a two-dimensional grid of cells using the {{w|Moore neighborhood}} - this means that each cell can only be influenced by the eight cells directly surrounding it, both orthogonally and diagonally. The transition rules that Conway discovered are as follows:

* If an "alive" cell has no live neighbors, or only one live neighbor, it becomes "dead". (This simulates death by isolation).
* If an "alive" cell has four or more live neighbors, it becomes "dead". (This simulates death by overcrowding).
* If a "dead" cell has exactly three live neighbors, it becomes "alive". (This simulates birth).

Despite the simplicity of these three rules, Conway showed that patterns of amazing complexity can nonetheless develop out of simple cell arrangements. Some patterns do not evolve at all ("still lifes"), some enter a cyclic, repeating state ("oscillators"), and some reproduce their own pattern displaced by an offset, resulting in patterns that can move across the grid under their own power ("gliders" and "spaceships"). This last category is of particular interest, as it allows the Game of Life to transmit information from one location to another, allowing for rich, dynamic behavior and even for the creation of computational machines within the automaton itself.

This comic begins with the shape of a stick figure as the starting cell configuration of the Game of Life. The black cells are "alive" and the white cells are "dead". This configuration then evolves via Conway's rules, disintegrating into nothingness except for a five-cell pattern known as a "glider", which ascends up and to the right. This visually suggests a "soul" breaking away from the disintegrating corporeal body. The glider is perhaps the most iconic pattern of the Game of Life, and is often used symbolically to represent the phenomenon of emergence.

The initial state presented in the comic does actually evolve in that manner, as can be verified by entering the pattern into a cellular automaton simulator such as [http://golly.sourceforge.net/ Golly] or web services such as [https://bitstorm.org/gameoflife/ this one].

The title text simply states Conway's birth and death year: 1937-2020.

Conway's Game of Life was previously mentioned in [[696: Strip Games]].

This comic may be the 18th comic in a row (not counting the [[2288: Collector's Edition|April Fools' comic]]) in a [[:Category:COVID-19|series of comics]] related to the {{w|2019–20 coronavirus outbreak|2020 pandemic}} of the {{w|coronavirus}} {{w|SARS-CoV-2}}, which causes {{w|COVID-19}}.

==Table of generations==
{| class="wikitable"
!Generation
!Notes
|-
|[[File:Generation 0.jpg|thumb]]||Starting state (or "zeroth generation").
|-
|[[File:Generation 1.jpg|thumb]]||First generation. Note that this image is not aligned with the previous one: the position of all cells has shifted downward by one cell. All further generations are aligned the same as this one.
|-
|[[File:Generation 2.jpg|thumb]]||Second generation.
|-
|[[File:Generation 3.jpg|thumb]]||Third generation.
|-
|[[File:Generation 4.jpg|thumb]]||Fourth generation.
|-
|[[File:Generation 5.jpg|thumb]]||Fifth generation.
|-
|[[File:Generation 6.jpg|thumb]]||Sixth generation. The first appearance of the glider, a well-known formation in Conway's Game of Life.
|-
|[[File:Generation 7.jpg|thumb]]||Seventh generation. The glider takes on its other shape.
|-
|[[File:Generation 8.jpg|thumb]]||Eighth generation. The glider returns to its first shape, pointing right instead of up.
|-
|[[File:Generation 9.jpg|thumb]]||Ninth generation. The glider's second shape again, pointing right instead of up.
|-
|[[File:Generation 10.jpg|thumb]]||Tenth generation. The glider is now in its original form, but one cell higher and one cell to the right. It will continue to progress, cycling through these four states every four generations. The remains of the chaos down below will take two more generations to disappear completely.
|}

==Transcript==
:[A pixelated image of a stick figure using 21 pixels, could be a pixel Cueball, which waves with one hand up while holding the other hand down. The head consist of 7 pixels, the top row of three having two pixels beneath the two outer pixels, thus having two empty pixels beneath the central pixel. The neck and torso is a typical cross made from six pixels. The two legs are two pixels each shifted left and right of the cross. The arm to the left that waves is two pixels one down and the next back up to the level of the cross central beam. The arm to the right has the first pixel similarly but the second pixel continues one further step down. After less than one second it turns out that the image is animated, with the pixels changing according to the rules of Conway's Game of Life. The figure splits into three groups, two of which dissipates in a similar way at the bottom of the panel. The other becomes a 'glider' and moves off to the top-right corner of the image and out of the frame. The animation then repeats.]

{{comic discussion}}

[[Category:Tribute]]
[[Category:COVID-19]]
[[Category:Comics with animation]]
[[Category:Comics featuring real people]]

2293: RIP John Conway

2020-04-15T17:03:06Z

172.69.34.44: move to bottom of explanation, not directly related to covid-19

{{comic
| number = 2293
| date = April 13, 2020
| title = RIP John Conway
| image = rip_john_conway.gif
| titletext = 1937-2020
}}

==Explanation==
{{incomplete|Created by a GLIDER. Needs more in-depth explanation of how the Game Evolves. Include remaining stills from the GIF in the table below. Should also expand more on why Conway is a person of note. Do NOT delete this tag too soon.}}

{{w|John Horton Conway|John Conway}}, an English mathematician, passed away of COVID-19 on April 11, 2020. Two days later, [[Randall]] created this [[:Category:Tribute|memorial comic]]. It is the 6th memorial comic, but it is the first released in almost 5 years, since [[1560: Bubblegum]].

One of Conway's most famous creations was the {{w|cellular automaton}} known as {{w|Conway's Game of Life}}. A cellular automaton is a machine composed of cells, each of which can be in a different state. Every generation, each cell in the automaton may transition to a new state depending on a set of rules. (Conway's work in mathematics was vast and various, but he is perhaps best known in the field for discovering the {{w|surreal numbers}}, which inspired Donald Knuth to write a novel which may have been referenced back in [[505: A Bunch of Rocks]].)

Conway's Game of Life is a 2-state automaton (i.e., every cell can be "alive" or "dead") that is implemented on a two-dimensional grid of cells using the {{w|Moore neighborhood}} - this means that each cell can only be influenced by the eight cells directly surrounding it, both orthogonally and diagonally. The transition rules that Conway discovered are as follows:

* If an "alive" cell has no live neighbors, or only one live neighbor, it becomes "dead". (This simulates death by isolation).
* If an "alive" cell has four or more live neighbors, it becomes "dead". (This simulates death by overcrowding).
* If a "dead" cell has exactly three live neighbors, it becomes "alive". (This simulates birth).

Despite the simplicity of these three rules, Conway showed that patterns of amazing complexity can nonetheless develop out of simple cell arrangements. Some patterns do not evolve at all ("still lifes"), some enter a cyclic, repeating state ("oscillators"), and some reproduce their own pattern displaced by an offset, resulting in patterns that can move across the grid under their own power ("gliders" and "spaceships"). This last category is of particular interest, as it allows the Game of Life to transmit information from one location to another, allowing for rich, dynamic behavior and even for the creation of computational machines within the automaton itself.

This comic begins with the shape of a stick figure as the starting cell configuration of the Game of Life. The black cells are "alive" and the white cells are "dead". This configuration then evolves via Conway's rules, disintegrating into nothingness except for a five-cell pattern known as a "glider", which ascends up and to the right. This visually suggests a "soul" breaking away from the disintegrating corporeal body. The glider is perhaps the most iconic pattern of the Game of Life, and is often used symbolically to represent the phenomenon of emergence.

The initial state presented in the comic does actually evolve in that manner, as can be verified by entering the pattern into a cellular automaton simulator such as [http://golly.sourceforge.net/ Golly] or web services such as [https://bitstorm.org/gameoflife/ this one].

The title text simply states Conway's birth and death year: 1937-2020.

This comic may be the 18th comic in a row (not counting the [[2288: Collector's Edition|April Fools' comic]]) in a [[:Category:COVID-19|series of comics]] related to the {{w|2019–20 coronavirus outbreak|2020 pandemic}} of the {{w|coronavirus}} {{w|SARS-CoV-2}}, which causes {{w|COVID-19}}.

==Table of generations==
{| class="wikitable"
!Generation
!Notes
|-
|[[File:Generation 0.jpg|thumb]]||Starting state (or "zeroth generation").
|-
|[[File:Generation 1.jpg|thumb]]||First generation. Note that this image is not aligned with the previous one: the position of all cells has shifted downward by one cell. All further generations are aligned the same as this one.
|-
|[[File:Generation 2.jpg|thumb]]||Second generation.
|-
|[[File:Generation 3.jpg|thumb]]||Third generation.
|-
|[[File:Generation 4.jpg|thumb]]||Fourth generation.
|-
|[[File:Generation 5.jpg|thumb]]||Fifth generation.
|-
|[[File:Generation 6.jpg|thumb]]||Sixth generation. The first appearance of the glider, a well-known formation in Conway's Game of Life.
|-
|[[File:Generation 7.jpg|thumb]]||Seventh generation. The glider takes on its other shape.
|-
|[[File:Generation 8.jpg|thumb]]||Eighth generation. The glider returns to its first shape, pointing right instead of up.
|-
|[[File:Generation 9.jpg|thumb]]||Ninth generation. The glider's second shape again, pointing right instead of up.
|-
|[[File:Generation 10.jpg|thumb]]||Tenth generation. The glider is now in its original form, but one cell higher and one cell to the right. It will continue to progress, cycling through these four states every four generations. The remains of the chaos down below will take two more generations to disappear completely.
|}

==Transcript==
:[A pixelated image of a stick figure using 21 pixels, could be a pixel Cueball, which waves with one hand up while holding the other hand down. The head consist of 7 pixels, the top row of three having two pixels beneath the two outer pixels, thus having two empty pixels beneath the central pixel. The neck and torso is a typical cross made from six pixels. The two legs are two pixels each shifted left and right of the cross. The arm to the left that waves is two pixels one down and the next back up to the level of the cross central beam. The arm to the right has the first pixel similarly but the second pixel continues one further step down. After less than one second it turns out that the image is animated, with the pixels changing according to the rules of Conway's Game of Life. The figure splits into three groups, two of which dissipates in a similar way at the bottom of the panel. The other becomes a 'glider' and moves off to the top-right corner of the image and out of the frame. The animation then repeats.]

{{comic discussion}}

[[Category:Tribute]]
[[Category:COVID-19]]
[[Category:Comics with animation]]
[[Category:Comics featuring real people]]

Talk:2293: RIP John Conway

2020-04-15T17:01:13Z

172.69.34.44: cmt

This is really very impressive. The design of the stick figure to allow it to release a glider that ascends upwards (the "soul" rising to "heaven" or whatever) with the body decaying - that's a hard thing to get right using just the Game of Life rules. [[Special:Contributions/172.69.68.175|172.69.68.175]] 17:49, 13 April 2020 (UTC)
:Although Randall is clever, the Game of Life has been studied for so long that I'm sure this is a well-known animation. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 18:29, 13 April 2020 (UTC)
:: I played with the game a bunch in the past, but I've only done a bit of research after this appeared. I don't immediately find any previous report of this starting arrangement
:: This is unlikely, as the Game of Life has an uncountable number of patterns of this size, some of which are still being discovered. The pattern above is 7 cells wide by 9 cells tall - the number of distinct patterns that can be drawn in that box nears 2 --> 60 --> 1 (2^60). It's most likely that patterns such as this one are commonplace, and Randall just fiddled around until he reached one that he desired. The pattern itself, however, has likely never been discovered before. (As a fun postscript, [http://catagolue.appspot.com/object/xp16_0c2w3vz33032988/b3s23 a notable 8-cell wide, 9-cell tall pattern oscillating at period 16], just slightly larger than the one above, was discovered in February 2020.)[[User:Hdjensofjfnen|Hdjensofjfnen]] ([[User talk:Hdjensofjfnen|talk]]) 21:31, 13 April 2020 (UTC)
:::I suspect it's probably more likely that he worked it out backwards, rather than "just fiddled with it." [[Special:Contributions/108.162.216.244|108.162.216.244]] 04:24, 14 April 2020 (UTC)
::::AFAIK, many CAs such as Life have the property of being irreversible, which is the entire point for various pattern search efforts.[[Special:Contributions/162.158.92.54|162.158.92.54]] 07:13, 14 April 2020 (UTC)
:::::He probably started with the floater, and adjusted the rest so it wouldn't interfere. Most figures decay in the game of life (I learned when playing with it, decades ago) --[[Special:Contributions/162.158.111.79|162.158.111.79]] 10:45, 14 April 2020 (UTC)
:::::The Game of Life has been researched a lot. One sub-problem is finding an arrangement of cells that cannot be produced by a prior arrangement of cells. They are called Garden of Eden patterns, and the known ones are not small. Glider generators are rather common, so it is most likely that the initial pattern was created by working backward from an existing glider generator.[[Special:Contributions/173.245.54.125|173.245.54.125]] 17:33, 14 April 2020 (UTC)

was there a placeholder comic posted before the gif went live?

:I am certain there was one with "uh oh one of the lights went out" "that's not supposed to happen" and a picture of a pattern that I did not recognise, which I found to be quite sad. [[Special:Contributions/162.158.92.54|162.158.92.54]] 10:35, 14 April 2020 (UTC)

::This was SMBC, and the pattern is a glider generator. [[Special:Contributions/188.114.111.211|188.114.111.211]] 12:30, 14 April 2020 (UTC)

Looks like this is second animated comic in xkcd, besides 1116(though 1190 could be possibly counted together) [[Special:Contributions/172.69.190.16|172.69.190.16]] 19:34, 13 April 2020 (UTC)
:Uh, [[1331: Frequency]] and [[1264: Slideshow]] immediately come to mind, and then I remember about [[961: Eternal Flame]]. There's a lot more than two. [[User:Volleo6144|Volleo6144]] ([[User talk:Volleo6144|talk]]) 19:43, 13 April 2020 (UTC)
::[[:Category:Comics with animation]]; just added it. [[User:Yngvadottir|Yngvadottir]] ([[User talk:Yngvadottir|talk]]) 20:19, 13 April 2020 (UTC)

The explanation says that the simulation is run on an infinite grid, but even when the grid is calculated out beyond the border of the viewable area, bounding errors & boundary formations can occur. I've never seen ''any'' implementation that actually produces an infinite, nor even ''practically'' infinite grid. (In fact, wasn't there a Minecraft mod that runs until it lags out the engine?) Can anybody point me to a truly infinite grid implementation? Conway's ''definitely'' was not infinite, he even commented at length about the boundary formations that show up at the grid edges (which are among the most subjectively beautiful, incidentally). I think the explanation needs correction?
[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 21:59, 13 April 2020 (UTC)
: The explanation is describing Conway's game of life, not any particular implementation IMHO. No change needed IMHOA. Also, the previous post was not signed properly. [[Special:Contributions/162.158.107.167|162.158.107.167]] 21:47, 13 April 2020 (UTC)
::Except many of Conway's observations about the "game" & even ''his initial description'' of it explicitly state & indeed hinge upon the fact that it's not (& thus far ''cannot'' be) implemented as an "infinite" grid. Part of the whole point of his experiment with it & the various demonstrations is to illustrate edge effects resulting from a finite range of calculations. '''It's extremely relevant that it's''' '''''not''''' '''infinite.''' It's actually kinda the whole point of his creating it, much the same way people working with fractals likewise tend to become very interested in bounding errors. The boundaries are where the interesting work is done. Apparently someone agreed with me at least in part, because they edited the wording. Thanks... Brian? I think we should actually '''add''' to the description of the "game" info highlighting the edge effects, because that's the primary focus of the project & its outgrowths in the first place. (We can't adequately simulate infinity & that's a big part of the interest in it.) Also, I frequently have to submit & then refresh & sign afterward because of the device I'm on. In this case I'm glad I did, because I saw your reply & the other new stuff!
::[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 22:17, 13 April 2020 (UTC)
:Golly uses a grid of arbitrary size by default. It can very easily be verified to at least ±210000. (Note that it also includes finite rectangular and toroidal grids.) [[User:LegionMammal978|LegionMammal978]] ([[User talk:LegionMammal978|talk]]) 01:39, 14 April 2020 (UTC)
No computer [Citation Needed] can run an ''actual'' infinite grid, but with some intelligent bounding you can mitigate early signs of problems by maintaining "bubbles" of cells with offsets. You get into problems once you start machine-gunning out gliders (offsets will eventually overflow or awkwardly lose precision, depending on the var-types used; and maintaining a longer and longer bubble, or more and more bubbles just above glider-sized, is probably your other challenge) but it's probably good enough for most purposes. If you somehow have finite patterns that move out in huge (wasteless) cycles from the 'origin' and hold that path until enacting hugely-delayed doglegs (mathematically, it must be a point no further away than can be reasonably enumerated by the bits of information contained within each formation, and significantly less as it'd be a far less efficient count-down cycler than any folded LFSR, but it's ''imaginable'') to meet again at some arbitrary (though deterministic and replicable) distance out in the far far reaches of your abstracted bubble-land then it's possible you could ''pretend'' you have infinite space. [[Special:Contributions/162.158.91.101|162.158.91.101]] 22:26, 13 April 2020 (UTC)

[[User:ProphetZarquon|ProphetZarquon]], do you have a source for your claim that the main point of Conway's creation of Life was to study the edge effects? [https://conwaylife.com/wiki/Conway%27s_Game_of_Life The page for Life on its own wiki] describes the Life grid as "infinite" and only mentions edge effects as inaccuracies to be avoided, and [https://www.youtube.com/watch?v=R9Plq-D1gEk this Conway interview about Life's creation] doesn't mention edges at all.
[[Special:Contributions/108.162.241.24|108.162.241.24]] 23:34, 13 April 2020‎ (UTC)
:First of all, as a tip, reply directly to the comment when you want to talk with someone. Secondly, yeah, I'm pretty sure that person's just blasting ass ham. [[Special:Contributions/172.69.69.28|172.69.69.28]] 02:49, 14 April 2020 (UTC)

Possibly worth noting is the bit of artistry in the rendering. Munroe alters the step period of the iterations so that the deconstruction of the humanoid shape happens more quickly, with the stepping of the glider translating away occurring more slowly. [[User:Fixer|Fixer]] ([[User talk:Fixer|talk]]) 21:52, 13 April 2020 (UTC)

I like the comic very much, and I'm afraid to say I hadn't heard of his death in amongst... well, everything else. RIP.
While I'm here, though, I'm a bit concerned about the current cell generation cycle explanation, as it feels awkward. Currently it is (paraphrased) "live cells survive if just enough neighbours / dead cells come to life with exactly enough neighbours / any other dies or stays dead". I'd prefer something that more delineates it as birth (dead to live, by propogation from the right number of live neighbours), death (live to dead due to ''either'' isolation ''or'' overcrowding) and continuation of state in all other cases. Can't work out a good phrasing yet, but ''may'' try it out later. [[Special:Contributions/162.158.91.101|162.158.91.101]] 22:26, 13 April 2020 (UTC)
: Agreed 100%. I believe the problem lies in the confusion between "cell as in biology" versus "cell as in jail". It would be better to avoid the word "cell" and describe a grid with squares that are either inhabited or empty; inhabitants with two or three neighbours survive to the next generation, otherwise they die (square becomes empty the next generation); exactly three neighbours to an empty square will give birth (become inhabited) in the next generation; and any other empty square stays empty.

Given the cause of death, should this comic be listed among the Covid-19 series? [[User:Momerath|Momerath]] ([[User talk:Momerath|talk]]) 05:02, 14 April 2020 (UTC)
:Yes.--[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 10:51, 14 April 2020 (UTC)
:No. This is about John Conway. It would have presumably run regardless of the cause of death.

Interesting to see if the next comic is also a Covid-19 comic, because then it will be the 19th covid-19 comic... --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 10:53, 14 April 2020 (UTC)

I really think this should not be regarded as a Covid-19 comic, since it's a memorial one and the cause of death is not important for this comic. [[Special:Contributions/162.158.93.105|162.158.93.105]] 14:18, 14 April 2020 (UTC)
:Agree with the others, this is a memorial comic, NOT a COVID-19 comic. I feel like too many comics are being forced into the COVID-19 theme, when they have little to no relation. [[Special:Contributions/172.69.22.62|172.69.22.62]] 16:12, 14 April 2020 (UTC)
::Covid-19 is obviously not directly the topic of the comic, but it is related quite close. So I vote to re-add it to the category, but to put the mention of the connection with the other comics not into the explanation, or on its bottom. If this is acceptable, [[961: Eternal Flame]] should also be included to [[:Category:Cancer]]. --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 10:43, 15 April 2020 (UTC)
:::Of course this is one in the Covid series. Randall very rarely makes tributes and it has been 5 year since the last. Conway is not very famous, and had he died a year ago, chances are Randall would not have made this comic. But because he died of Covid while all Randall's comics is about Covid he makes a tribute now. For the same reason I do not think that Eternal flame has anything with the cancer category. Because this was a tribute Randall made without any connection to a series of cancer comics. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 11:25, 15 April 2020 (UTC)
::::Thanks for correcting my spelling errors :D all of that is speculation. How do you know, that Randall is not a huge Conway fan? seems to play exactly into his geekynes. --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 12:47, 15 April 2020 (UTC)
:::::I also disagree that Randall is not a huge Conway fan. I believe he would be familiar and interested in the Game of Life automata, as a nerd/geek. I agree with Lupo's suggestions for this comic. [[Special:Contributions/172.69.34.44|172.69.34.44]] 17:01, 15 April 2020 (UTC)

== Is this original? ==

It would seem remarkable if Randall was able to create this starting pattern at such short notice. If it's copied from somewhere, we should provide that detail. [[User:Stevage|Stevage]] ([[User talk:Stevage|talk]]) 03:54, 15 April 2020 (UTC)
:I do not know if it is taken from another place or a common/known pattern (the comments above seem to suggest otherwise), but it is not uncommon to have an obituary / memorial in stock for elderly persons of relevance. So it might be possible, that e.g. Randall played around with putting stick figures into a simulation, and accidently found this, deciding to keep it somewehere in his archive for this occasion. The seperation of the decaying body and the everlasting part going upward is actually obvious enough to connect with the idea to use it for this occasion. --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 10:36, 15 April 2020 (UTC)

2291: New Sports System

2020-04-09T01:49:14Z

172.69.34.44: /* Transcript */ re-add tag, don't remove too early

{{comic
| number = 2291
| date = April 8, 2020
| title = New Sports System
| image = new_sports_system.png
| titletext = Under my system, boxing and football suffered, pair figure skating still worked but had to adapt by dropping some moves, and pro wrestling was actually completely unaffected.
}}

==Explanation==
{{incomplete|Created by a VIRTUAL BALL. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
This comic is the 16th comic in a row (not counting the [[2288: Collector's Edition|April Fools' comic]]) in a [[:Category:COVID-19|series of comics]] related to the {{w|2019–20 coronavirus outbreak|2020 pandemic}} of the {{w|coronavirus}} {{w|SARS-CoV-2}}, which causes {{w|COVID-19}}.

As communities have been ordered to stay indoors to avoid spreading the virus, this has also affected sports leagues around the world, with many of them suspending their seasons, or cancelling them outright. (see {{w|Impact of the 2019–20 coronavirus pandemic on sports|this Wikipedia article}} for a full list of sports or sporting events impacted) Some leagues have instead promoted e-sports, such as the [https://www.latimes.com/sports/clippers/story/2020-04-06/patrick-beverley-favorite-to-win-nba-2k-players-tournament NBA holding an ''NBA 2K20'' tournament between active NBA players].

[[Randall]], in this comic, proposes a "new sports system" of "virtual sports", in which players play with a virtual ball in separate arenas, and are guided by online viewers. This obviously proves to be challenging, as the ball is virtual and thus the players do not know how to interact with it properly. Playing in separate arenas would solve the problem of spreading the virus, as the players do not have any direct interactions with each other.

This would be a similar system to the {{w|Twitch Plays Pokémon}} experiment from February 2014 on Twitch, in which Twitch viewers "played" Pokémon video games in a crowdsourced manner.

In the title text, Randall claims that boxing and football (unclear if American football or international football) proved to be difficult, with {{w|Pair skating|pairs figure skating}} still possible, and {{w|professional wrestling}} being unaffected. Boxing and any types of football would be difficult to play in these situations, without knowing where the other players are located. Pairs figure skating would be possible, excepting "throwing" moves or "lifts", as typically pairs figure skaters skate in unison, replicating the same moves.

Humorously, Randall claims that professional wrestling will be unaffected by his new system. This is in reference to the "open secret" that the matches have predetermined outcomes and are more "entertainment" than actual competition.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[Single wide frame representing a basketball court with a basketball goal at each end. There are seven players running around the court, with a virtual ball in the bottom right corner (indicated by being drawn as a dashed circle). Nine off-screen voices of "online viewers" are yelling instructions to the players. A caption is below the frame running nearly the full width of the frame.]

:Viewer One: No!
:Viewer Two: It's on the–
:Viewer Three: Look out!
:Viewer Four: No!
:Viewer Five: He's right there. Don’t run into–
:Viewer Six: Go left!
:Viewer Seven: Riiight!
:Viewer Eight: Left!
:Viewer Nine: Stop dunking and find the ball!

:Caption: No one liked my new sports system, in which each player is in a separate arena sharing a single virtual ball that they can't see while online viewers yell instructions, but it was fun to watch while it lasted.

{{comic discussion}}
[[Category:COVID-19]]
[[Category:Sport]]
[[Category:Basketball]]
[[Category:American football]]
[[Category:Multiple Cueballs]]