explain xkcd - User contributions [en]

2236: Is it Christmas?

2019-12-04T03:24:32Z

172.68.142.77: /* Explanation */

{{comic
| number = 2236
| date = December 2, 2019
| title = Is it Christmas?
| image = is_it_christmas.png
| titletext = We've tested it on 30 different days and it hasn't gotten one wrong yet.
}}

==Explanation==
{{incomplete|Created by a BOT (99.73% accurate). Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
https://isitchristmas.com/ is a popular simplistic website that informs the visitor whether or not it's {{w|Christmas}}. Christmas is a holiday observed on December 25 of each year. At the top on the tab of the site in the browser it says "Is it Christmas?" with a large '''NO''' printed if it is not Christmas, and a '''YES''' if it is Christmas. This website does a check on the computer's current date, and updates accordingly if it is indeed Christmas. In addition, isitchristmas.com gives the answer in the language of your region (i.e. a visitor from Canada will give the answer in English and French to account for Canada's bilingularity, and in most other countries just their word for No will be shown). Since the page uses the computers time settings, it is possible to easily check that the page works by changing the date on the computer used to access the page, to see the text change to Yes (or No if you are reading this on Christmas Day). This also means that the page is only as correct as the time setting on the computer used to view the page.

Here [[Randall]] spoofs the website. He claims to have made a competitor to isitchristmas.com which nearly always correctly tells if it is Christmas. The joke is, that the comic will always display a static image reading '''NO''', even on Christmas Day, and that the rare incorrect answer is rare enough to not cause any concern.

Randall lists a rounded calculation of 99.73% for the precision of his prediction of whether or not it is Christmas. This number is accurate with or without including leap year. An average year is 365.25 days, meaning that he is only wrong 1 out of 365.25 days. So only 1/365.25 = 0.2737% of the days would the prediction be wrong, resulting in a correct reply rate of 99.726%, which he has rounded to 99.73%. Using or not using the leap year will give the same result to three decimal places.

Although Randall's claim on {{w|Accuracy and precision#In binary classification|accuracy}} is true, accuracy alone doesn't make a predictive device useful. In this case, the page {{w|False positives and false_negatives#false negative rate|miss rate}} or false negative rate, that is, the percent of positive condition days (it's Christmas) that are predicted by the comic not to be Christmas, is 100%. In other words, it misses all actual events of Christmas.

When building a model for rare events, a common mistake is to ignore the implicit cost function built into the standard prediction accuracy validity statistic for binary events. Prediction accuracy (# correct guesses/total guesses) assumes that false positives and false negatives are equally bad. Given the implicit cost function of this performance statistic, the best-performing model is commonly a persistence forecast model--ie, the optimal prediction model returns the most common value whatever the model inputs are. It's probably a better choice to optimize a model using a performance statistic which relies on a cost function that penalizes missing correct prediction of rare events more than it penalizes missing correct prediction of common events.

In fact, in most settings where a single outcome is a lot more common than any other one, predicting always that most common outcome would yield very high accuracy without any usefulness. It isn't hard to find examples even more accurate than Randall's:

* A useless test for AIDS giving always negative results would have an accuracy about 99.95% when applied to a random human, and even more if used in countries with low prevalence of AIDS.
* A website saying "You are not the cartoonist Randall Munroe" would be right for 99.9999999857% of humans.
* [https://knowyourphrase.com/even-a-broken-clock-is-right-twice A stopped watch is accurate twice a day] while a running watch is almost never accurate (and oddly, is more accurate the faster/slower it runs).

The title text is a "proof" that his service works. He claims to have tested this on 30 different days and confirmed that NO is the correct result. Any date except Christmas would result in a correct result, and the comic was the first to be released in December 2019, so unless the test had run for almost a year, he would not even have had a chance to test this on Christmas Day. Since this is a joke, the comic will of course not change to Yes on Christmas Day, because then it would be 100% accurate, as is the page the comic mocks.

Being right on most days, but not the one that mattered was also the subject of [[937: TornadoGuard]].

==Transcript==
:[A large square white panel with one large word in the middle, plus a footnote:]
:'''<big><big><big>No*</big></big></big>'''
:<nowiki>*</nowiki>99.73% accurate

:[Caption below the panel:]
:xkcd.com presents a new "Is It Christmas" service to compete with isitchristmas.com

==Trivia==
*Randall usually makes [[:Category:Christmas|Christmas comics]] around Christmas Day, but this year he has made two comics mentioning Christmas already by the 2nd of December 2019.
**The first came two comics before this with [[2234: How To Deliver Christmas Presents]].
**Only two times before has there been released any Christmas related comics so close to Christmas without being released in the few days around Christmas Day (22-26 of December). See the explanation for Christmas comics.

{{comic discussion}}

[[Category:Christmas]]

2133: EHT Black Hole Picture

2019-04-06T02:52:58Z

172.68.142.77:

{{comic
| number = 2133
| date = April 5, 2019
| title = EHT Black Hole Picture
| image = eht_black_hole_picture.png
| titletext = [five years later] Ok, it seems we were accidentally zoomed in slightly too far. But imagine there's a cool-looking twisted accretion disc just outside this black square!
}}

==Explanation==
{{incomplete|Created by cosmic rays from a black hole Needs more explanation Do NOT delete this tag too soon.}}
This comic references the {{w|Event Horizon Telescope}}, an international project dedicated to releasing the first-ever picture of a {{w|black hole}}. The release of the picture is set for April 10, five days from this comic's release.

The comic shows [[Cueball]] giving a press conference on the recent photographing of a black hole. The joke lies in the spectacular failure of several systems:

* You cannot download the picture.
* You cannot screenshot the picture.
* The viewing period ends before a physical camera can be used.

In reality, none of this should be an issue as the picture would be immediately saved by the system and would not need to be downloaded from the site.

Cueball describes the system as being like {{w|Pinterest}}, where CSS prevents you from right-clicking on an image so that you could save it. Cueball states that they then tried to take a screenshot, but the key combination to make a screenshot instead turned off the monitor where the picture was being displayed. This references the fact many mobile phones incorporate the power button in their screen shot combination and the power button can also turn off the screen. Laptops and operating systems may also have undocumented key combinations that blank the screen, which users can accidentally press when in a hurry and create further stress for themselves. As a last act of desperation, Cueball took out his phone and attempted to take a photo of the observation, but by that time, the observation had ended, and the photo was lost.

Cueball then states that they would try to take a picture of a black hole again next year.

The title text explains that (after presumably five years of annual tries), the picture failed again as the telescope was too zoomed in and only captured a featureless square. Since a black hole by definition returns no light sent to it, the photograph would be entirely black. Researchers however are primarily presumably trying to obtain images of the more interesting edge known as an {{w|accretion disc}}, which could actually be meaningfully photographed.

*ps:You can actually download images from pinterest by using browser's inspector

==Transcript==
:[Cueball is standing behind a lectern, with "Press Conference" and the EHT logo displayed on a projector screen behind him.]
:Cueball: We linked up our observatories, got everything aligned, and there it was:
:Cueball: The first image of a black hole!

:Out of panel: Can you share the picture?
:Cueball: Well, here's the thing...

:Cueball: Turns out our telescope feed is like Pinterest, where you can't right-click to save an image.
:Cueball: So we tried to take a screenshot, but the key combination kept turning off the display instead.

:[The projector screen has changed to show a blurry picture of a white computer screen against a black background. The EHT logo remains.]
:Cueball: I grabbed my phone and tried to take a picture of the screen, but I was too slow. The observation had ended.
:Cueball: We're planning to try again next year, and we'll definitely record the screen this time.

{{comic discussion}}

[[Category:Comics featuring Cueball]]

2131: Emojidome

2019-04-01T17:39:52Z

172.68.142.77: Changed 4PM utc to 16:00 for consistency

{{comic
| number = 2131
| date = April 1, 2019
| title = Emojidome
| image = emojidome.png
| titletext = 🤼🤼🤼🤼🤼🤼🤼🤼
}}
*To experience the interactivity, visit the {{xkcd|2131|original comic}}.

==Explanation==
{{incomplete|Created by 😇. Needs more elaboration on font influencing emoji..}}

This is an interactive [[:Category:April fools' comics|April fools' comic]] that began at 16:00 UTC on April 1, 2019 in which users are shown two emoji roughly every 38 seconds, and vote for their favorite. The competing candidates are periodically overlaid with heart emojis that up float from the vote button oscillating in a sinusoidal pattern before disappearing above the candidate, and may represent real-time votes for each emoji. Supposedly, the emoji will be eliminated one-by-one until there are a final two emoji facing off, with the one most voted-for being crowned the best emoji. This is likely a parody of March Madness.

As of 17:30 UTC, we are still in the first round of voting brackets, according to the match-up schedule in the link.

Note that the schedule might show different emoji pictures then the main voting screen, presumably because of fonts. The image is pre-rendered.

The competing candidates are chosen in order of unicode value at first, resulting in similar emojis being compared. Examples include:

😜 squaring off against 😛 - two emoji playfully sticking their tongues out

🤩 squaring off against 😍 - two smiling emojis with symbols for eyes

😂 squaring off with 🤣 - two emojis that are crying in laughter/joy.

The title text may appear to be nonsense. If so, your browser may not be parsing the title text correctly. It consists of the wrestlers emoji (🤼) eight times over.

A robot face announcer-emoji (🤖) and a link to the full bracket was added at 38 minutes in. https://www.xkcd.com/2131/emojidome_bracket.png shows 512 emojis in a single-elimination tournament.

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

{{comic discussion}}

[[Category:April fools' comics]]
[[Category:Interactive comics]]

User:Netherin5

2019-03-26T21:24:13Z

172.68.142.77:

I hate red on wikis.

I’ve done {{#cscore:Netherin5|changes}} things, though most of those are fixing my own mistakes. I’ve edited {{#cscore:Netherin5|pages}} pages for a total of {{#cscore:Netherin5|score}} point things. Keep calm and wiki on.

I have also said the words “Demon Core is lesser”, so free cool points for me.

Talk:2124: Space Mission Hearing

2019-03-15T17:11:49Z

172.68.142.77: signed comment

Spaceship noises? What exactly does a spaceship sound like if you can't hear anything in space? Perhaps this is part of the joke! [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 13:15, 15 March 2019 (UTC)
:Actauly you can - your own spaceship might be producing some sounds. Like sort of humming device.
::Spaceships sound like the computer-generated chirps, whistles, and whooshes used in sci-fi media to make travel through space familiar to those of us who travel through air. I hear little 'pew pew pew' noises come from my computer whenever I burn a cd! [[Special:Contributions/172.68.65.198|172.68.65.198]] 13:49, 15 March 2019 (UTC)
:::they add them artificcially like on electric cars, so that you do not get run over by a spaceship when crossing the milkyway. --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 14:12, 15 March 2019 (UTC)

And I see that main idea behind this comics - that while we are trying to find some serious reasoning of space programms, the real motive that realy matters - IT IS SPAAAAAAACE!!! Everything else is not enough to justify such expences.
: It could be meaningful to list some reasons for exploring or not exploring space in the article ... There's a TV show about colonizing Mars that makes the point that once we inhabit two planets, we guarantee a future for our race if the planet doesn't survive. [[Special:Contributions/172.68.65.198|172.68.65.198]] 13:49, 15 March 2019 (UTC)
:: Indeed, the main reasons for exploring space are (so very human) curiosity and need of achievement. Like exploring the lands and seas of Earth in the previous centuries (even if greed was a big factor as well). The former is more rational and largely more fruitful than the latter, in the sense that pursuing curiosity we (the humanity) learn new things while exploring space and advance general science and technology, which eventually (in some cases) leads to improvements of daily life. The need of achievement (hurray! we're first to do it!) is what mostly drives manned exploration, which also provides some scientific results but comes at a vastly greater cost. Given current and near-future advances in robotics, mechatronics, etc. the scientific value/cost quotient of manned exploration is very low compared to robotic missions in my opinion. I'd vote for building a thousand of Mars probes that will take some measurements in a thousand of points on the planet's surface over doing a manned mission that'll visit one spot - for a comparable price. But humans are not entirely rational beings and sometimes do crazy things just for the sake of them. Colonization on the other hand is a completely outworldlish idea. The colony would not survive without constant resupply from Earth - not in any forseeable future state of technology. Maybe in thousands of years, maybe never (i.e. we'd go extinct before we could achieve it). -- [[User:Malgond|Malgond]] ([[User talk:Malgond|talk]]) 14:47, 15 March 2019 (UTC)

I’m glad there’s now a comic featuring literally me. Complicated explanation prior to yelling space and making laser noises. [[User:Netherin5|Netherin5]] ([[User talk:Netherin5|talk]]) 14:23, 15 March 2019 (UTC)

The "Spaaaaaace" reminds me of the "Spaaace" substitution in 1288. Probably just a coincidence. [[Special:Contributions/172.68.142.77|172.68.142.77]] 17:11, 15 March 2019 (UTC)

Talk:2124: Space Mission Hearing

2019-03-15T17:11:20Z

172.68.142.77:

262: IN UR REALITY

2019-03-08T17:54:40Z

172.68.142.77: Added another link with staple references.

{{comic
| number = 262
| date = May 16, 2007
| title = IN UR REALITY
| image = in_ur_reality.png
| titletext = Hey, at least I ran out of staples.
}}

==Explanation==
The {{w|LOLcat}} meme genre involves pictures of cats in various poses and facial contortions accompanied by deliberately misspelled captions. Black Hat claims to be from the Internet and is thus creating LOLcat memes by literally gluing captions to Cueball's cats.

The title text suggests that Black Hat is using glue only because he ran out of staples; fortunately for the cats in the picture, glue is much less painful than a staple. The title is also a reference to the "I'm in ur base killing ur d00dz" [http://knowyourmeme.com/memes/in-ur-base catchphrase] from real-time-strategy games.

Stapling things to other things has also been referenced in [[291: Dignified]] and [[478: The Staple Madness]].

==Transcript==
:[Black Hat is holding a cat and a piece of paper. Cueball has raised his arms. There are three cats with captions stuck to them.]
:Black Hat: Oh hi; I'm here from the Internet.
:Cueball: What are you doing!?
:Black Hat: Gluing captions to your cats.
:Cat: ''rrrr''

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Black Hat]]
[[Category:Internet]]

982: Set Theory

2019-02-09T00:35:29Z

172.68.142.77: Wood chippers do not define well-orderings

{{comic
| number = 982
| date = November 25, 2011
| title = Set Theory
| image = set_theory.png
| titletext = Proof of Zermelo's well-ordering theorem given the Axiom of Choice: 1: Take S to be any set. 2: When I reach step three, if S hasn't managed to find a well-ordering relation for itself, I'll feed it into this wood chipper. 3: Hey, look, S is well-ordered.
}}

==Explanation==
This comic is a pun on the phrase "{{w|Proof by Intimidation}}" which normally is a jocular term used mainly in mathematics. It refers to a style of presenting a purported mathematical proof by giving an argument loaded with jargon and appeals to obscure results, so that the audience is simply obliged to accept it, lest they have to admit to their ignorance and lack of understanding.

However, in this comic, "Proof by Intimidation" is taken to mean that by intimidating the elements within a set, they will conform to the proof (or, as the title text says, they will become "well-ordered"). This is accomplished by believing that the elements can be {{w|anthropomorphize}}d such that they feel fear. The idea of executing as an example was exemplified by Sun Tzu in the ancient book {{w|The Art Of War}}.

The {{w|axiom of choice}} (which has been referenced previously in [[804: Pumpkin Carving]]) says that given any collection of bins, each containing at least one object, it is possible to make a selection of exactly one object from each bin. It was later referenced in the title text of [[1724: Proofs]], another comic about a math class with a similar theme on how teachers teach their student mathematical proofs.

In the title text, the well-ordering theorem states that every set can be well-ordered. A set X is well-ordered by a strict total order if every non-empty subset of X has a least element under the ordering. This is also known as {{w|Zermelo's theorem}} and is equivalent to the Axiom of Choice. The woodchipper is a reference to the 1996 film {{w|Fargo (film)|Fargo}}, where a character uses one to dispose of a body.

It might seem there is another layer to the joke: if you can feed the set to the wood-chipper, that defines an ordering on the set (the order in which the elements are fed to the wood chipper). However, that doesn't actually work, because the resulting ordering is not necessarily well-ordered. For example, consider the set of positive real numbers. You can imagine feeding half a number line to a wood chipper from the end near zero. This defines the standard less-than ordering, but it is not a well-ordering because it does not define a least element. For any positive number x, x/2 went into the wood chipper first. The set may be motivated to find a well-ordering, but it won't be the standard one.

==Transcript==
:[Ponytail stands at a blackboard, facing away from it. She has a pointer in her hand, and written on the blackboard is some set theory math, although one of the set elements is being pointed into a guillotine.]
:Ponytail: The axiom of choice allows you to select one element from each set in a collection
:Ponytail: and have it ''executed'' as an example to the others.
:My math teacher was a big believer in Proof by Intimidation.

{{comic discussion}}

[[Category:Comics featuring Ponytail]]
[[Category:Math]]
[[Category:Logic]]
[[Category:Puns]]

Talk:2104: Biff Tannen

2019-01-28T17:17:13Z

172.68.142.77:

I thought Biff jumped from 2015 to 1955, not 1985...? Young Biff had the Almanac in his pocket at the High School dance and the tower he built was already in place in 1985.


Collusion with a time traveler would bring a few things into focus. [[Special:Contributions/173.245.54.25|173.245.54.25]] 15:24, 28 January 2019 (UTC)
:You inspire ''one'' house painter to change careers & suddenly everyone blames you for everything.
:[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 16:23, 28 January 2019 (UTC)

https://en.wikipedia.org/wiki/Hillbilly_Elegy
[[Special:Contributions/172.68.65.198|172.68.65.198]] 15:39, 28 January 2019 (UTC)

2101: Technical Analysis

2019-01-21T05:04:00Z

172.68.142.77: /* Explanation */

{{comic
| number = 2101
| date = January 21, 2019
| title = Technical Analysis
| image = technical_analysis.png
| titletext = "I [suspect] that we are throwing more and more of our resources, including the cream of our youth, into financial activities remote from the production of goods and services, into activities that generate high private rewards disproportionate to their social productivity. I suspect that the immense power of the computer is being harnessed to this 'paper economy', not to do the same transactions more economically but to balloon the quantity and variety of financial exchanges." --James Tobin, July 1984
}}

==Explanation==
{{incomplete| Comic is still undergoing TECHNICAL ANALYSIS. Do NOT delete this tag too soon.}}

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

{{comic discussion}}

Talk:2098: Magnetic Pole

2019-01-15T13:49:15Z

172.68.142.77:

GPS relies on satellites not the magnetic pole, so it wouldn't be affected.
: I originally mentioned that modern GPS receivers like in smartphones may integrate the compass, gyro, and GPS to provide higher-quality location data using heuristics, which may get fouled-up if the pole moves too far, but I wrote it in too playful a manner and it has been deleted since. There was no citation anyway; it was just a vague memory. [[Special:Contributions/162.158.79.245|162.158.79.245]] 06:08, 15 January 2019 (UTC)

So, GPS ''receivers'' don't need magnetic poles... but what about the GPS ''satellites''? GPS works being them transmitting their exact location, so they need so way of knowing what that is. [[User:JamesCurran|JamesCurran]] ([[User talk:JamesCurran|talk]]) 22:58, 14 January 2019 (UTC)

I was wondering about that. Just added {{Citation needed}} to that and a couple of other alleged facts that should really be cited if true, and removed if not. [[Special:Contributions/108.162.216.208|108.162.216.208]] 20:35, 14 January 2019 (UTC)

It was speculated that reversals were linked to mass extinctions. This would make the alt-text appear to be a bit blase - but " Statistical analysis shows no evidence for a correlation between reversals and extinctions." so it seems we will probably be OK.
It does seem odd that GPS wouldn't be calibrated against fixed ground positions. [[User:Baldrickk|Baldrickk]] ([[User talk:Baldrickk|talk]]) 22:06, 14 January 2019 (UTC)

I expect we'll be fine, but don't a lot of migratory critters use the Earth's magnetic field for navigation over very long distances? I mean, it's not as though they check a calendar and say, "Oh, hey, winter's coming, I guess I'd better head North." They just go in the direction they are 'programmed' to go when they start to feel the urge to do so. So... If the poles reverse (or whatever else) aren't they going to go the wrong direction? There are lots of other species that rely on those migratory species for their lunch. Yeah, I can imagine that there could be a lot of problems. Assuming, of course, that what I read about migratory species using the magnetic field of the Earth for navigation is true.[[Special:Contributions/162.158.79.143|162.158.79.143]] 02:39, 15 January 2019 (UTC)

I don't believe any "location systems" depend on magnetic field for their accuracy, other than a magnetic compass. As noted above, GPS is calculated numerically from signals received from satellites, so the only effect the magnetic field could have on that is if it somehow disrupts the broadcast of the satellite radio signals. Similarly, LORAN calculates location based on radio signal, from towers on land. There are others as well, and I'm pretty sure none that depend on the location of the magnetic pole. GPS in general is not calibrated to fixed ground positions, but there are enhancements to GPS that do. But those still use radio broadcasts from towers whose locations are known, and don't need to take into account the location of magnetic north.
[[User:Lnthomp|Lnthomp]] ([[User talk:Lnthomp|talk]]) 22:28, 14 January 2019 (UTC)

I agree that the way it is currently phrased is misleading (to the point of being wrong), but some "location systems" use multiple factors to increase their accuracy. A good smartphone will use GPS together with signal strengths to wifi routers with known locations together with its compass to increase accuracy above that which it could obtain from GPS alone. I've only taken little glimpses into the issue professionally but if I were making an algorithm for such a thing I'd also use input from the accelerometers. In any event, I'd most certainly use the built-in compass. Cheap estimation of direction of travel. Of course I'm just being pedantic with all of that. The difference in accuracy for such a scenario would most likely be minor to the point that nobody would notice. I just kind of think the algorithms that try to combine all that sensor data are cool. --[[Special:Contributions/162.158.62.51|162.158.62.51]] 01:24, 15 January 2019 (UTC)
:It's navigation systems rather than location/positioning systems that rely on magnetic field (although both are often combined). You need a compass to know which direction your are facing and how to go to your destination.[[Special:Contributions/141.101.104.11|141.101.104.11]] 11:32, 15 January 2019 (UTC)

Granted no one has ever experienced and documented a magnetic reversal event, however, would it be possible for the magnetic flux to cause errors on magnetic media? (eg HDD, credit cards, floppies, cassette, VHS, etc) If it were a cause for alarm, would a faraday cage be useful in protecting against the effects? [[Special:Contributions/172.68.34.34|172.68.34.34]] 23:05, 14 January 2019 (UTC)
: Faraday cages attenuate electric, not magnetic, fields. I think magnetic shielding involves thick, rounded material with high permeability such as iron, steel, mu-metal, often placed inside a faraday cage to prevent RF signals from saturating the permeability; never done it myself though. [[Special:Contributions/162.158.79.245|162.158.79.245]] 06:13, 15 January 2019 (UTC)

No. Magnetic media would not be affected. Geomagnetic field strengths are orders of magnitude weaker than those used to write to magnetic media. --[[Special:Contributions/162.158.62.51|162.158.62.51]] 01:27, 15 January 2019 (UTC)

The biggest issue during a magnetic pole reversal will be the loss of the Van Allen belt, frying all of us. [[User:RandalSchwartz|RandalSchwartz]] ([[User talk:RandalSchwartz|talk]]) 02:39, 15 January 2019 (UTC)
:Unlikely to literally fry us, but there could definitely be damages on the electrical grids around the world as the magnetic field is weakened during the transition. Probably also a rise in radiation-induced cancers.[[Special:Contributions/141.101.104.11|141.101.104.11]] 11:32, 15 January 2019 (UTC).

GPS and Solar weather [https://www.swpc.noaa.gov/impacts/space-weather-and-gps-systems citation ] - worth a read. Basically, the ionosphere disturbance from a changing Earth field (analogous to a changing solar wind) leads to notable inaccuracy and service disruption. [[Special:Contributions/108.162.221.167|108.162.221.167]] 23:12, 14 January 2019 (UTC)

We'll have to renumber all our runways, which will be annoying. [[Special:Contributions/162.158.58.111|162.158.58.111]] 04:27, 15 January 2019 (UTC)
:actually, several runways have already had to have been renumbered because of change in the magnetic poles.[[Special:Contributions/162.158.79.143|162.158.79.143]] 05:19, 15 January 2019 (UTC)

Wait, "geomagnetic reversal in the next few decades"? Last I checked, it was scheduled to happen in the next few ''millennia''. Have there been new data? [[Special:Contributions/141.101.104.131|141.101.104.131]] 09:00, 15 January 2019 (UTC)
:Reversals appear to happen randomly, so there's no way to know when the next one will happen. Even if the last one happened about 800 000 years ago, there have been periods of tens of millions of years without reversal.[[Special:Contributions/141.101.104.11|141.101.104.11]] 11:32, 15 January 2019 (UTC)
:https://www.sciencedaily.com/releases/2012/10/121016084936.htm might shed some light on things. In any case, “scheduled” is definitely the wrong word. [[Special:Contributions/172.68.142.77|172.68.142.77]] 13:49, 15 January 2019 (UTC)

Talk:2096: Mattresses

2019-01-11T05:09:26Z

172.68.142.77: Many advertisements used to be of this style in the early days of radio and television

'''Image quality'''


I wonder if the fact that it's unclear is in intentional, or if it was somehow a mistake [[User:Zachweix|Zachweix]] ([[User talk:Zachweix|talk]]) 13:46, 9 January 2019 (UTC)

Is it just me, or has the image got some graphical artifacts?[[User:Cyclic3|Cyclic3]] ([[User talk:Cyclic3|talk]])

It's not just you! [[Special:Contributions/141.101.96.221|141.101.96.221]] 13:52, 9 January 2019 (UTC)

I see it too, I saved a picture in case he fixes it [[User:Catnerd8695|Catnerd8695]] ([[User talk:Catnerd8695|talk]]) 14:09, 9 January 2019 (UTC)

Both "1x" and 2x versions are black and white, not grayscale, causing artifacts. The 2x image, being larger, have less artifacts. Maybe it's caused by some kind of bug, otherwise, if it was intentional, both versions would look similar.

Maybe Randall is having problems with his computer and had to scan the comic with a far less capable software tool than usual. [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 14:15, 9 January 2019 (UTC)

How does one contact him to let him know that he messed up when saving/editing/uploading/whatevering this comic? [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 14:16, 9 January 2019 (UTC)

Also, does he actually have a podcast? [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 14:18, 9 January 2019 (UTC)

I thought it might be a pun based on "new years resolution" but that would've been a couple of comics ago. Came here to see if anyone could explain it as there is normally reason behind his madness.--[[Special:Contributions/141.101.99.71|141.101.99.71]] 14:29, 9 January 2019 (UTC)

It's a 2-bit png, haven't seen one of those for over a decade [[Special:Contributions/172.68.215.112|172.68.215.112]] 14:31, 9 January 2019 (UTC)
:So you mean the only difference is that it has no greyscales? [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 14:36, 9 January 2019 (UTC)

Maybe we should pre-emptively add the original image to the trivia section. [[User:Blacksilver|Blacksilver]] ([[User talk:Blacksilver|talk]]) 15:07, 9 January 2019 (UTC)
:I don't think so. If it stays, nobody will get notified of it and it might stay there for a very long time. And even if it changes, it will be wrong to say something like "it originally looked like this" until that actually happened. [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 15:10, 9 January 2019 (UTC)
Just a thought, it's not on purpose, is it? Something to do with the quality of the mattress vs. the quality of the image? [[Special:Contributions/172.68.132.95|172.68.132.95]] 15:09, 9 January 2019 (UTC)
:Nope, I guess not, lol[[Special:Contributions/172.69.22.224|172.69.22.224]] 14:56, 10 January 2019 (UTC)

I think this refers to the fact that casper mattresses, meundies and stamps.com are heavy advertisers on many podcasts, and that podcast advertising is often made by the host and mixed with actual podcast content.
[[User:Dromaeosaur|Dromaeosaur]] ([[User talk:Dromaeosaur|talk]]) 15:20, 9 January 2019 (UTC)

Zooming fixes the issue. Would it be possible for someone to rescale it properly, and then set that as the image, until Randall fixes it? [[User:Cyclic3|Cyclic3]] ([[User talk:Cyclic3|talk]]) 15:25, 9 January 2019 (UTC)
:No, it does not. Your browser or image viewer might interpolate between white and black pixels if you zoom in, but that's actually an even lower image quality. And you might not notice it too much if you only look at a single line. But no, zooming does not fix it. [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 15:28, 9 January 2019 (UTC)
::Zooming makes some browsers load the 2x image, which had less artifacts than the normal image, "fixing" it. No interpolation was needed. You can test it by zooming (it it still don't loads the 2x version try reloading the page). {{unsigned|162.158.63.166}}
:::Not in Chrome at least. And I would also not expect my browser to load a new image just because I zoomed. And I can't try it anymore anyway, because the image is fixed now. [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 10:58, 10 January 2019 (UTC)
::::I use Chrome. You can still test the zoom feature, which still works with the current image as there's a 2x version: zoom to 200%, probably the image will get blurry (as, as you said, Chrome don't loads the higher resolution image automatically). Then reload the page then it will load the 2x version (which isn't blurry).

Any chance of steganography? {{unsigned|172.68.150.82}}
:What? What does that have to do with this comic? And what are you expecting to happen or have happened? [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 15:37, 9 January 2019 (UTC)

Hey, it's just been fixed! I'll start uploading the new one now. [[User:Jacky720|That's right, Jacky720 just signed this]] ([[User talk:Jacky720|talk]] | [[Special:Contributions/Jacky720|contribs]]) 15:46, 9 January 2019 (UTC)

:Instead of uploading as a new image in the wiki, shouldn't we just update the existing image with the new file? [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 16:07, 9 January 2019 (UTC)
::The comic image always has to be updated and the file name must NOT be changed. The name is the same as the comic name and appears automatically in some lists. While someone already had done the proper update I've changed the link at this explanation back to the original and deleted the now unnecessary duplicate. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 18:07, 9 January 2019 (UTC)

I removed this portion from the explanation - not sure that it is needed. (But here if want to improve/add back.)
"To reduce the chances that their listeners will skip or fast-forward through ads,"
Another reason for having the host read the advertisement would be cost reduction.
This style of advertisement is very similar to what is common on radio, and used to be very common in the early days of radio and television. (Again, not sure worth saying in the article.) [[Special:Contributions/172.68.142.77|172.68.142.77]] 05:09, 11 January 2019 (UTC)

'''Post Office'''

The named products are not from the comic and seem to reflect the writers bias. Besides postmates, it could as well be stamps.com. I am not sure, but I believe to remember that other matress and underware companies advertise on podcasts as well. --[[Special:Contributions/162.158.75.10|162.158.75.10]] 17:34, 9 January 2019 (UTC)
:There is no way that this is referencing Postmates. It's definitely Stamps.com -- which advertises on nearly every podcast I listen to. It also makes more sense -- the Stamps.com ad directly references avoiding going to the post office. Casper and Meundies also have to be correct -- listening to podcasts, that's basically all I hear.
[[User:Joefresco|User:Joefresco]] ([[User talk:User:Joefresco|talk]]) 18:03, 9 January 2019 (UTC)
:: I have heard a lot of adds about tommyjohn on Pod Safe America (https://medium.com/crookedmedia/crooked-codes-866128fda384) and Mack Weldon as well. They also have advertisements for Helix Sleep another mattress. I think there is a good reason the comic doesn't mention company names but product categories.--[[Special:Contributions/108.162.216.208|108.162.216.208]] 18:44, 9 January 2019 (UTC)

'''Floor'''

Next week there is actually a "flooring" fair in Hannover. Pretty fitting to the title text, but not very fitting to my plans for using trains, because that messes up their departure times.

German website for it: https://www.visit-hannover.com/Messen-Kongresse/Messekalender-Hannover/Messen-2019/DOMOTEX-Hannover-Service [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 15:18, 9 January 2019 (UTC)

2096: Mattresses

2019-01-11T05:02:33Z

172.68.142.77: /* Explanation */ simplify sentences, move descriptions of podcast advertising so all in one paragraph

{{comic
| number = 2096
| date = January 9, 2019
| title = Mattresses
| image = mattresses.png
| titletext = After reading that "The War To Sell You A Mattress Is An Internet Nightmare" article, I've decided it's safer and less complicated to just sleep on the floor. DISCLOSURE: THE AUTHOR OF THIS MOUSEOVER TEXT RECEIVED FINANCIAL COMPENSATION FROM THE FLOOR INDUSTRY FOR THIS MESSAGE.
}}

==Explanation==
{{incomplete|Created by a Podcast Host. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

Cueball is talking to Ponytail about his mattress, in what appears to be just a casual conversation. Cueball suddenly offers to take any questions from listeners, as though the conversation were part of a podcast; this confuses Ponytail. The subtitle explains that Randall has heard so many advertisements for certain products on podcasts that he assumes any mention of those products is part of a podcast.

{{w|Podcast}}s are typically audio-only programs available online which frequently generate income through advertisements. To reduce the chances that their listeners will skip or fast-forward through ads, ads are often read by the podcast host. Hosts will often include segues or personal anecdotes to further reduce the "topical whiplash" caused by abruptly switching subjects from that of the podcast to an unrelated brand plug, and back.

In 2018, many podcasts (or at least many podcasts that Randall listens to) contained ads by {{w|Casper Sleep|Casper}} (a mattress brand), MeUndies (an underwear brand), and {{w|Stamps.com}} (an internet-based mailing/shipping service).

The title text refers to [https://www.fastcompany.com/3065928/sleepopolis-casper-bloggers-lawsuits-underside-of-the-mattress-wars this article] about a mattress review site that makes money through affiliate sales, and its legal battle with a mattress company. It also references the way that podcast hosts will often note when they intentionally or unintentionally endorse a product sponsor in an attempt to remain transparent about their financial supporters.

==Transcript==

:[Cueball and Ponytail are talking to each other]
:Cueball: ...It's firmer than my old mattress, which I thought I wouldn't like, but it's actually really nice.
:Ponytail: Cool, maybe I should get one.
:Cueball: Now let's take some listener questions!
:Ponytail: What?

:[Caption below the panel:]
:I can't talk about mattresses, underwear, or the Post Office anymore without feeling the urge to segue back into a podcast.

==Trivia==
The image was originally posted without a smooth blur between black and white, leading to graphical artifacts. The original image can be seen [https://www.explainxkcd.com/wiki/images/archive/8/84/20190109163710%21mattresses.png here].

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Ponytail]]

2096: Mattresses

2019-01-11T04:53:09Z

172.68.142.77: rearrange - put the explanation first, then the details

{{comic
| number = 2096
| date = January 9, 2019
| title = Mattresses
| image = mattresses.png
| titletext = After reading that "The War To Sell You A Mattress Is An Internet Nightmare" article, I've decided it's safer and less complicated to just sleep on the floor. DISCLOSURE: THE AUTHOR OF THIS MOUSEOVER TEXT RECEIVED FINANCIAL COMPENSATION FROM THE FLOOR INDUSTRY FOR THIS MESSAGE.
}}

==Explanation==
{{incomplete|Created by a Podcast Host. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

In this comic, Cueball is talking to Ponytail about his mattress in what appears to be just a casual conversation. However, the conversation appears to transition into a typical podcast dialog when Cueball offers to take any questions from listeners; this confuses Ponytail. The subtitle explains that Randall has heard so many advertisements for certain products on podcasts that he assumes any mention of those products is part of a podcast.

{{w|Podcast}}s are typically audio-only programs available online, either through an RSS feed or a website, which frequently generate income for the hosting service through advertisements. In 2018, many podcasts (or at least many podcasts that Randall listens to) contained ads by {{w|Casper Sleep|Casper}} (a mattress brand), MeUndies (an underwear brand), and {{w|Stamps.com}} (an internet-based mailing/shipping service).

In addition, to reduce the chances that their listeners will skip or fast-forward through ads, ads are often read out by the podcast hosts. They will often include segues and personal anecdotes to further reduce the "topical whiplash" caused by abruptly switching subjects from that of the podcast to an unrelated brand plug, and back.

The title text references [https://www.fastcompany.com/3065928/sleepopolis-casper-bloggers-lawsuits-underside-of-the-mattress-wars this article] about a mattress review site that makes money through affiliate sales, and its legal battle with a mattress company. It also references the way that podcast hosts will often note when they intentionally or unintentionally endorse a product sponsor in an attempt to remain transparent about their financial supporters.

==Transcript==

:[Cueball and Ponytail are talking to each other]
:Cueball: ...It's firmer than my old mattress, which I thought I wouldn't like, but it's actually really nice.
:Ponytail: Cool, maybe I should get one.
:Cueball: Now let's take some listener questions!
:Ponytail: What?

:[Caption below the panel:]
:I can't talk about mattresses, underwear, or the Post Office anymore without feeling the urge to segue back into a podcast.

==Trivia==
The image was originally posted without a smooth blur between black and white, leading to graphical artifacts. The original image can be seen [https://www.explainxkcd.com/wiki/images/archive/8/84/20190109163710%21mattresses.png here].

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Ponytail]]

2095: Marsiforming

2019-01-07T16:14:43Z

172.68.142.77: /* Transcript */

{{comic
| number = 2095
| date = January 7, 2019
| title = Marsiforming
| image = marsiforming.png
| titletext = It has so many advantages--it preserves Martian life, requires fewer interplanetary launches, and makes it much easier to field-test Mars rovers.
}}

==Explanation==
{{incomplete|Created by a MARS ROVER. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

{{w|Terraforming}} is the (so far only suggested) process of changing a planet, usually to make it more habitable (for humans). A very common example is {{w|Mars}}, which is known to harbour water ice and believed to have previously been warm enough to have liquid water. Normally, plans for terraforming try to adjust temperatures to be compatible with liquid water, and an atmosphere containing significant amounts of oxygen but little carbon dioxide. In this comic [[Cueball]] is suggesting doing the opposite, and terraform {{w|Earth}} to be more like Mars, i.e. extremely dry, cold and with a very thin atmosphere. The word {{w|Terra}} is the latin name for Earth, so Terraforming would be "Earth Forming". The comic title combines Mars with Forming (with a linking "i") to create the new word Marsiforming.

The title text the provides examples of how this could improve things: Preserving martian life (if Earth became Mars, then Earth's inhabitants could be called Martians, thus changing the goal to preserving humans), fewer interplanetary launches (no need to leave this planet's atmosphere in order to visit itself), easier to field-test Mars rovers (testing them on Earth would be sufficient for Earth-renamed).

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

[Cueball is on a stage giving a presentation, with a diagram behind him]

Cueball: Earth and Mars may look different now, but with some orbiting mirrors and atmospheric adjustments, we could change that.

[Caption below the panel:]

I'm having trouble selling people on my proposal to terraform Earth to resemble Mars.

{{comic discussion}}

2091: Million, Billion, Trillion

2018-12-28T07:46:07Z

172.68.142.77:

{{comic
| number = 2091
| date = December 28, 2018
| title = Million, Billion, Trillion
| image = million_billion_trillion.png
| titletext = You can tell most people don’t really assign an absolute meaning to these numbers because in some places and time periods, “billion” has meant 1,000x what it's meant in others, and a lot of us never even noticed.
}}

==Explanation==
{{incomplete|This needs about a thousand years of rewriting, and I assume we'll want to do a chart of X and Y positions as with most chart comics. Do NOT delete this tag too soon.}}
Much like [[558: 1000 Times|comic 558]], this comic addresses the difficulty ordinary people have with large numbers. Though most if not all people intuitively understand the difference between one object and two objects, or one object and ten objects, or even one object and a hundred objects, as numbers increase most people's ability to innately conceive of the numbers being discussed decreases remarkably quickly. When numbers reach the millions and the billions, and especially the trillions, most people don't truly process the numbers at all, and instead conceive of them as some version of a drastically-oversimplified concept such as "very big." Where comparing one to ten is simple, comparing "very big" to a different "very big" can prove extremely challenging, and will certainly require non-intuitive, conscious thinking.

The comic represents this challenge by providing a graph which represents [[Randall]]'s ''intuitive'' conception of the values of various very large numbers, and said conception's misalignment with reality. Though some trends reflect the real value of the numbers on the graph, i.e. 100 million larger than 10 million larger than 1 million and 1 billion larger than 1 million, the curve is far from the linear (exponential on the log-scaled axes) path it should take, with 1 billion being intuitively understood as less than 100 million, based, presumably, on the fact, easily comprehended on an intuitive level, that '''100 is larger than 1''', and therefore the presence of 100 in 100 million places it at a higher value than the 1 in 1 billion would place the latter. In reality, of course, 1 billion is ten times larger than 100 million, but the comic deals not with actual reality, but with the perception of reality of these numbers '''before conscious thought is applied'''.

The most interesting parts of the graph, and the parts where the disconnect between intuition and reality becomes clearest, are the dashed sections labeled with question marks, the one between 100 million and 1 billion, the other between 100 billion and 1 trillion. Here two competing intuitive understandings compete for dominance. On the one hand, the intuitive understanding described above, with 100 trumping 1, would see the curve taking a sharp downturn. On the other hand, the path from 100 million to 1 billion is paved with such numbers as 500 million, 700 million, and 900 million, all of which would theoretically be seen intuitively as larger than 100 million, thanks to the fact that 9 is greater than 7, and 7 greater than 5, and so on, bending the curve up rather than down. These two conflicting intuitions leave Randall with no single intuitive path for the two dashed sections, leading to their dashed and questioned state.

The comic's caption and title highlight another problem surrounding the intuitive grasping of large numbers: the flaws in the English words used for them. For instance, nothing about the world "million" suggests smallness relative to the world "billion" on an intuitive scale. This unintuitive language contributes greatly to the "100 trumps 1" intuitive fallacy described above.

The title text references a classic, and highly relevant, example of a disconnect between British and American English. For all English speakers, 1 million constitutes 1,000 thousands, or, said less ambiguously, 10^6. However, the definition of billion varies depending which side of the Atlantic Ocean you happen to land on. In America, 1 billion equals 1,000 millions, or 1000*10^6=10^9. [https://en.oxforddictionaries.com/explore/how-many-is-a-billion/ In Britain], 1 billion equals ''1 million'' millions, or 10^6*10^6=10^'''12''' (for those immediately asking "what did they call a thousand million, then?", the answer is the profoundly weird ''"milliard"''). In other words, 1 billion objects in England would register as 1,000 billion objects to an American, despite the fact that the number of objects has remained the same. Though people in Britain often use the American definition as of the past few decades, the fact that such a staggering difference of terminology was able to remain, and be almost completely unknown, perfectly highlights Randall's point about the failure of human intuition, and English terminology, in the discussion of extremely large numbers.

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

{{comic discussion}}

801: Golden Hammer

2018-07-26T23:19:39Z

172.68.142.77: /* Explanation */ Added incomplete tag

{{comic
| number = 801
| date = October 4, 2010
| title = Golden Hammer
| image = golden hammer.png
| titletext = Took me five tries to find the right one, but I managed to salvage our night out--if not the boat--in the end.
}}

==Explanation==
[[incomplete|In English please! This first paragraph is gobbledegook to the non-Java savvy.
{{w|Java}} is a programming language touted for its Portability™, which sometimes leads to it being used in systems where it really just shouldn't be used. [[Cueball]] laments that the hardware he's tinkering with, despite being used for a single purpose, has its firmware written in Java; since the microprocessor is unknown, it's quite possible the {{w|Java Virtual Machine}} (JVM) had to be ported over to the processor before the hardware designers could write firmware for it. Presumably, they considered this worthwhile to be able to write the control code in a language they're comfortable with, even though it probably would have been much simpler to just write the control code in whatever language they used to port the JVM in the first place.

[[Black Hat]] explains that this is really an example of an age-old adage: "When all you have is a hammer, everything looks like a nail", also referred to as the "{{w|law of the instrument}}" or, as in the title, the "golden hammer". The hardware developers probably only knew Java, and when they thought about how to write firmware for their new device, "Java" was the only solution that occurred to them.

Of course, instead of a hammer and a nail, Black Hat's analogy is about using bolt-cutters and vodka to get through the lock on {{w|Wolf Blitzer}}'s boathouse. Not-so-coincidentally, Black Hat is holding a pair of bolt-cutters and a bottle of vodka. The implication is that Black Hat ''did'', in fact, break into Wolf Blitzer's boathouse the previous night, which is why he has just now entered the door at the start of the strip. The changes he makes to the adage implies that he believes vodka and boltcutters are designed specifically to be used on Wolf Blitzer's boathouse, an interpretation that fits Black Hat's warped and anarchic disposition. As he is carrying both of these items, it also implies that he has just used those instruments for exactly that purpose. Cueball however, being extremely jaded by the (mis)use of Java, can only bring himself to tell that he's glad that Black Hat had a nice night.

The title text implies that Black Hat had to break into a number of boathouses before he found Wolf's, and that his boat did not survive the evening. The use of the phrase 'our night' allows us to infer that Black Hat may have been with [[Danish]], his partner in crime.

==Transcript==
:[Black Hat is going through a door, a bottle in his hand. A voice speaks to him from off panel.]
:Cueball: Seriously? This thing runs ''Java?'' It's single-purpose hardware!

:[Cueball is sitting at a computer, holding some device which is wired to a box, and pointing at the screen.]
:Cueball: I bet they actually hired someone to spend six months porting this JVM so they could write their 20 lines of code in a familiar setting.

:[Black Hat has a pair of bolt cutters in the hand that had been obscured in the first panel.]
:Black Hat: Well, you know what they say— When all you have is a pair of bolt cutters and a bottle of vodka, everything looks like the lock on the door of Wolf Blitzer's boathouse.
:Cueball: I'm glad ''you ''had a nice night.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Black Hat]]
[[Category:Programming]]
[[Category:Language]]

1282: Monty Hall

2018-04-13T22:57:54Z

172.68.142.77: Just FYI: Recapta is shut down...

{{comic
| number = 1282
| date = October 25, 2013
| title = Monty Hall
| image = monty hall.png
| titletext = A few minutes later, the goat from behind door C drives away in the car.
}}

==Explanation==
This comic is a reference to the US game show ''{{w|Let's Make a Deal}}'', and more specifically the {{w|Monty Hall problem}}, a probability puzzle based on the show and named after its original host, {{w|Monty Hall}}. The premise of the show was that Hall would offer "deals" to contestants pulled from the audience in which they could win cash and prizes. Some deals involved games/tasks the contestant had to perform, while others simply involved the contestant making choices between a series of doors or boxes. In such games of choice, there were often several prizes and typically at least one "zonk", the show's name for an undesirable "gag" prize, which on the original Monty Hall version of the show were frequently animals such as goats.

In the {{tvtropes|MontyHallProblem|classic version of the Monty Hall Problem}}, a contestant is offered a choice of three doors. Behind two of the doors are goats, and behind one of them is a car. First, the contestant chooses a door, which remains closed. The host then opens one of the two remaining doors and reveals a goat. The contestant is then offered a final choice of whether to switch their choice to the remaining closed door, or keep the door they originally chose. The problem involves an analysis of the probability of the contestant choosing the car given certain circumstances.

The problem assumes that a contestant would want to win a car, and would be disappointed to win a goat, which most contestants would have no ability to house, and no use for. The comic shows that [[Beret Guy]], upon the host revealing that door B has a goat behind it, chooses to take the goat to keep as a pet, which makes them both very happy. This is much like, and may be an allusion to, the Simpsons episode {{w|Bart Gets an Elephant}}, in which Bart opts for the gag prize of an African Elephant rather than the $10,000 award. According to an [http://www.tvparty.com/gamemonty2.html interview] with Monty Hall, several contestants actually decided to keep the animals; although rare, it was allowed since the animals were offered as prizes (and they were a lot more expensive than the consolation cash prize).

The title text references the car and the remaining goat, untouched behind the remaining doors.

===The Monty Hall Problem===
:''For an in-depth analysis of the Monty Hall Problem, see {{w|Monty Hall Problem|its article at Wikipedia}}''
The apparent "paradox" of the Monty Hall Problem is that many people's initial reaction once the host opens a door to reveal a goat, is that there are two remaining doors, one with a car and one with a goat; and therefore there is an equal probability the car is behind each door. Many people therefore believe that switching makes no difference to the odds of winning a car.

[[File:montyforexplainxkcd.png]]

However, assuming that the host has knowledge of which doors contain goats, and that their choice of which door to open is always an unchosen door containing a goat, it is actually twice as likely that the contestant will win the car if they switch than if they keep their original choice. This is because the contestant initially had a one-in-three chance of choosing the car and a two-in-three chance of choosing a goat. Switching always wins the car in those two-thirds of cases where the contestant initially chose a goat. The probability of winning by switching is therefore the same as the probability that the contestant initially chose a goat.

The switch essentially gives the contestant ''both'' remaining doors instead of just the ''one'' door originally chosen. Because the host ''always'' has at least one goat available, the fact that the host reveals a goat does not provide the contestant any new information about their initially chosen door. The initial door still has a two-in-three chance of being a goat, and switching still has a two-in-three chance of winning. Opening a goat-door simply shifts all of the probability of the remaining two doors being a car to the remaining unchosen door.

'''Simple explanation''':
Imagine there are 100 doors instead of just 2, and after you pick a door, the host opens all but one, revealing all goats. Do you switch to the remaining door or keep your initial pick? Just as there is a 2/3 chance of picking the car when switching in the 3-door scenario, there is now a 99/100 chance of picking the car when switching in the 100 door scenario. In this scenario, it becomes obvious that it is not a 50/50 chance when two doors remain.

'''Important Side Note''':
There has been great debate about the precise wording of the problem, and what assumptions or rules might apply. These variants can greatly change the probabilities.

One variant has the host open one of the two remaining doors at random, which could result in the car being revealed, and the game ending. In that scenario, if a goat has been revealed, the probability that the first pick is correct is now 1/2 and switching is not advantageous.

:*In 1/3 of all possible games, the first pick is correct. The host cannot pick the car.
:*In 1/3 of all possible games, the first pick is wrong but the host does not reveal the car.
:*In 1/3 of all possible games, the first pick is wrong and host will reveal the car. We now know those cases are impossible.

With only 2/3rds of all possible games remaining, the chance that switching will win the car is now (1/3)/(2/3) = 1/2. Likewise, not switching also has a 1/2 chance of winning. '''Note that this variant requires that the host picks a door at random.'''

Another variant has the host only offering to switch if the first choice is correct. In this case, switching always loses.

==Transcript==
:[A figure - Monty Hall - stands on stage, holding a microphone. There are three doors; two labelled "A" and "C", which are closed, and one that is being held open by Monty. There's a ramp to the right, down which a goat is being led by Beret Guy.]
:Beret Guy: ...and my yard has so much grass, and I'll teach you tricks, and...
:Goat: ♥

==Trivia==
*The Monty Hall problem is strikingly similar to the {{w|Two envelope problem|Two Envelope Paradox}}, one of [http://blog.xkcd.com/2008/09/09/the-goddamn-airplane-on-the-goddamn-treadmill/ several notoriously provocative thought experiments] (some of which are "banned" on the xkcd forums). Admittedly, the Monty Hall problem has only one clear solution. Because of this, it is much less likely to spark the kinds of arguments like "the goddamn airplane on the goddamn treadmill" or the "{{w|Feynman sprinkler}}" incite.

{{comic discussion}}
[[Category:Comics featuring Beret Guy]]

1967: Violin Plots

2018-03-14T09:02:40Z

172.68.142.77:

{{comic
| number = 1967
| date = March 14, 2018
| title = Violin Plots
| image = violin_plots.png
| titletext = Strictly speaking, 'violin' refers to the internal structure of the data. The external portion visible in the plot is called the 'viola.'
}}

==Explanation==
{{incomplete|Created by GEORGIA O'KEEFFE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
{{w|Violin plot|Violin 🎻 plots}} look like female genitals.

Strictly speaking, this strip is not purely a violin plot; it is a violin plot overlayed onto a line plot.

The title text invokes the fact that many people incorrectly use the word "{{w|vagina}}", which refers to an internal structure, for the {{w|vulva}}, which is the external portion of the female genitals. Meanwhile the {{w|viola}} is an instrument often mistaken for a {{w|violin}}. And the word "viola" sounds similar to "vulva."

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

{{comic discussion}}

1799: Bad Map Projection: Time Zones

2017-02-15T07:32:25Z

172.68.142.77: Stylistic edits

{{comic
| number = 1799
| date = February 15, 2017
| title = Bad Map Projection: Time Zones
| image = bad_map_projection_time_zones.png
| titletext = This is probably the first projection in cartographic history that can be criticized for its disproportionate focus on Finland, Mongolia, and the Democratic Republic of the Congo.
}}

==Explanation==
{{incomplete|First draft}}This comic shows a [[wikipedia:Map projection|map projection]] in which countries are placed according to the [[wikipedia:Time zone|time zones]] that they fall under. Based on the way the Sun shines on the Earth, these time zones, which are based on the sun's position in the sky, would best be divided by roughly longitudinal (North-to-South Pole) lines.

However, this is not the case in practice, as the defined time zones tend to have very jagged boundaries. Since [[Randall]] knows he cannot fix the boundaries of the time zones, he instead "fixes" the world by making a map appear to match up with the time zone system. This results in bizarre distortions such as the large, gum-like strands of Greenland and enormous gulfs in parts of northern Russia.

Due to the projection, small countries that happen to cross the boundaries of time zones appear as much wider than they actually are. Conversely, countries that choose to use fewer timezones, such as China, appear far thinner than their geographic shapes. Other map projections distort countries this way as well, but based on their actual physical location as opposed to their position on imaginary time zones. The [[wikipedia:Mercator projection|Mercator projection]] is infamous for distorting Greenland in this way, to the point that it appears to be larger than Africa despite being nowhere near the same size. The title text lampoons the fact that the same phenomenon occurs on Randall's bad map projection, but for countries that do not tend to experience this on typical projections. Several smaller, lesser-known countries such as Finland, Mongolia, and the DRC, appear much larger than their actual size due to being stretched across time zone boundaries.

==Transcript==
{{incomplete transcript}}
:Bad map projection #79:
:'''Time Zones'''
:Where each country should be,
:based on its time zone(s)

{{comic discussion}}