explain xkcd - User contributions [en]

Talk:Countdown in header text

2022-01-15T22:36:43Z

162.158.106.105:

The talk on from [[2565: Latency]] and [[2566: Decorative Constants]] has been moved here by me when I created this page --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 11:01, 12 January 2022 (UTC)

;From Latency:
What is happening around Feb 1st, there is a countdown that appeared a few hours ago in the upper right corner of the xkcd index. There is also the directory xkcd.com/count-wimRikmef which might be an acronym, if it isnt a countdown package? {{unsigned ip|172.70.130.57}}
:Damn you beat me to it ;-). But I have made a [[2565:_Latency#Trivia|Trivia]] here on this comics page and links to more detail on the [[xkcd Header text]] page. I belie you are a day of, but someone will likely correct me if I'm wrong. As I can see it will be January 31st, 9:59 in Randall's home town Boston.--[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 20:06, 10 January 2022 (UTC)
::But damned if I can wait. Sure millions will watch the page when it goes to zero! At least it is no April 1st. :-D --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 20:10, 10 January 2022 (UTC)

;From Decorative Constants
Any idea what's going on with the clock that's counting downwards in the banner? Currently counting down from 20 days 16 hours? [[Special:Contributions/172.70.214.95|172.70.214.95]] 22:08, 10 January 2022 (UTC)
:(Simultaneous edit) What is the days-hours-minutes in the box above the comic referring to? The image itself is dated yesterday, as you can see by saving it. Worst-case-scenario, is this a countdown to the end of XKCD? [[Special:Contributions/108.162.245.223|108.162.245.223]] 22:11, 10 January 2022 (UTC)
:: It's going to hit zero at around midnight on Jan 31st 2022 CST? [[User:SteveBaker|SteveBaker]] ([[User talk:SteveBaker|talk]]) 22:16, 10 January 2022 (UTC)
:::'''Posted this on the previous comics discussion. But lets take it here where there will be more traffic:''' --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 22:44, 10 January 2022 (UTC) -- Copy paste from previous comics discussion:
::::Damn you beat me to it ;-). But I have made a [[2565:_Latency#Trivia|Trivia]] here on this comics page and links to more detail on the [[xkcd Header text]] page. I believe you are a day of, but someone will likely correct me if I'm wrong. As I can see it will be January 31st, 9:59 in Randall's home town Boston.--[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 20:06, 10 January 2022 (UTC)
:::::But damned if I can wait. Sure millions will watch the page when it goes to zero! At least it is no April 1st. :-D --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 20:10, 10 January 2022 (UTC)
::::Yeah - you're right - I messed up. So as I type this, it's Jan 10th 2022 at 4pm - 1600 hrs Mountain time - which is 1800 hours EST. At this moment, the countdown reads 20d 16h 0m - so Jan 30th + (18+16) hours = which is Jan 30th + 34 hours - which is Jan 31st + 10am in Boston (EST). [[User:SteveBaker|SteveBaker]] ([[User talk:SteveBaker|talk]]) 23:05, 10 January 2022 (UTC)
:::::Hey great, can see they agree in the link to reddit below. So happy I got it right both in UTC and Boston. It will be 15:59 here in DK. Not 16:00. ;-) --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 23:44, 10 January 2022 (UTC)

Counting down to Backwards Day? --[[Special:Contributions/162.158.91.88|162.158.91.88]] 23:28, 10 January 2022 (UTC)
:There's a reddit thread discussing it: https://www.reddit.com/r/xkcd/comments/s0oynl/xkcd_countdown_timer_20d_21h_49m_remaining_until/ I think the most likely guess is that Randall has a new book coming out. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 23:40, 10 January 2022 (UTC)
::Would still seem strange if it came out that day with only promotion before being a count down. But then again, he will have the xkcd communities boiling if he gives no other hint. So every one will see if he promotes a book. Also as they wrote at the time I looked at reddit I do not think it is the end of xkcd, or Webb related. Although Webb was the first I thought about. But I mean even if it came to L2 at that day, it is not going to any specific point but just in orbit. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 23:47, 10 January 2022 (UTC)

::The date fits the idea of it being Backwards Day (https://nationaldaycalendar.com/backward-day-january-31) but what about the choice of time? [[User:SteveBaker|SteveBaker]] ([[User talk:SteveBaker|talk]]) 03:38, 11 January 2022 (UTC)
:::Backwards day... Never head of it until now. Is it big in the US. I mean when looking after dates so obscure they are not mentioned on wikipedia then there are probably lots of things happening on that day? But maybe it is a think in the US? --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 08:48, 11 January 2022 (UTC)
:::: I haven't heard of it until now either, so it is probably one of the bajillions of holidays no one actually cares about, and is unrelated to the countdown. [[Special:Contributions/108.162.221.163|108.162.221.163]] 13:22, 11 January 2022 (UTC)Bumpf

Someone has noticed the image is changing with pixels added at the bottom left corner and is keeping track of it here: https://munvoseli.github.io/xkcd-countdown/ [[Special:Contributions/198.41.238.107|198.41.238.107]] 05:49, 11 January 2022 (UTC)
:Looks like an image is "moving" into the frame because at the moment you can see some white pixel in the lower left, i.e. the black part might end up as a line as part of some comic. [[Special:Contributions/162.158.89.8|162.158.89.8]] 08:31, 11 January 2022 (UTC)
::Thanks used that to pinpoint the start of the countdown. Have added this info to the header text page, and the original trivia. Also just added a line of trivia to this explanation with the link. This was when this comic came out most people noticed the count down. But it did came out while [[Latency]] was up. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 08:43, 11 January 2022 (UTC)
:::Speculating on what it could be, the only thing that makes sense at that angle is a character's arm. 04:47, 12 January 2022 (UTC)

The header changes page says that it's forcing "Friday" to move down to the next line. Not for me. Did he fix it, or is it browser-specific? [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 14:58, 11 January 2022 (UTC)
:It must be browser specific. But i have tried bot the old Internet Explorer, Edge, Chrome and Firefox, and it does it in all cases and zooming does nothing.. Which browser do you use? I have corrected to in some browsers though, in the [[xkcd_Header_text#2022-01-10_-_Standard_text_with_countdown|explanation]] you refer to. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 15:31, 12 January 2022 (UTC)

This is much more likely a count down related to the James Webb Space Telescope. At approximately the day the count down indicates the telescope will be orbiting the L2 gravitational spot.Perhaps most of the mirrors will be approximate place to allow for months of fine tuning. An example of a slightly similar idea is https://www.space.com/nasa-james-webb-space-telescope-next-steps
[[User:Punchcard|Punchcard]] ([[User talk:Punchcard|talk]]) 15:35, 11 January 2022 (UTC)
:I really do not think so. There is nothing special about a specific moment for reaching L2. It will go in orbit around it, but when to day it is there or in orbit is hard to pinpoint. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 11:13, 12 January 2022 (UTC)
::And after I looked at it, it seems it will reach L2 several days before the countdown. See [[Countdown in header text#Theories]]. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 15:31, 12 January 2022 (UTC)

I think the Countdown should get its own entry. What do we think? [[User:Sure|Sure]] ([[User talk:Sure|talk]]) 16:25, 11 January 2022 (UTC)
: I think it should! What with the count itself, the speculation about what it could mean, and now the slowly arriving image (?) this seems like something beyond either of the two comics since it started! [[Special:Contributions/108.162.219.49|108.162.219.49]] 18:00, 11 January 2022 (UTC)
: I'm surprised it doesn't have one already. This is one of the more unique situations in a long while, more speculation could happen. [[User:Thisfox|Thisfox]] ([[User talk:Thisfox|talk]]) 22:26, 11 January 2022 (UTC)
::I have now created this page and talk page for us to continue the discussion and make dedicated changes about this countdown here. And have moved all discussion from the two pages that had some already (except a few on the first talk page that was also mentioned here. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 11:13, 12 January 2022 (UTC)

If you take a look at this [[https://xkcd.com/count-wimRikmef/state|link]] it displays this: '''{"img":"72cb154b23f959f908f5dc8eb03069c6df3f0f54aae896a0e7ed27befb2ee639.png","start":"2022-01-10T17:00:00Z","target":"2022-01-31T15:00:00Z","until":"2022-01-11T20:55:38.205303701Z"}''' [[User:Hoodiesandboba|Hoodiesandboba]] ([[User talk:Hoodiesandboba|talk]]) 20:58, 11 January 2022 (UTC)
:To correct your link:
:"...If you take a look at this [https://xkcd.com/count-wimRikmef/state link] it displays..."
:As to where the "72cb154b23f959f908f5dc8eb03069c6df3f0f54aae896a0e7ed27befb2ee639.png" is rooted, I haven't dug into that (or what transforms might be being applied), but it looks like a manipulation of browser states might be able to prematurely reveal it. (I'm on mobile at the moment, and it's significantly more fiddly to poke into the page-scripting and markup than I can be bothered with this moment, but I know what I'd do with a good acreage of screen, mouse control and a proper keyboard to rattle away at. And the combined minds here surely can do even better than myself.) [[Special:Contributions/172.70.91.116|172.70.91.116]] 22:38, 11 January 2022 (UTC)
::The filename is a random number long enough to prevent brute force guessing to find future images. The state-file looks like some information for the javascript script where this URL comes from. I haven't looked into the script that much but from the values I'd say that it's telling when to start doing refreshs (2022-01-10T17:00:00Z) and when to stop doing that (2022-01-31T15:00:00Z). While these values are constant, the third value changes and is ten minutes after the time the page has been requested. I suppose this is telling the script, when to do a refresh of the image load. [[Special:Contributions/141.101.77.16|141.101.77.16]] 11:05, 13 January 2022 (UTC)
:::After some fiddeling, I've found the origin of the filename: It's the SHA-256 hash of the image [[Special:Contributions/141.101.77.16|141.101.77.16]] 11:05, 13 January 2022 (UTC)
::::There's already a note that it would be impossible to brute-force the filenames. But as the images are very similar to each other, would it be feasible to programmatically generate images similar to the last one (extending up and to the right, different variations of the line shape), hash those files, and test to see if they match images on the server? I'd expect it to reduce the number of possibilities by orders of magnitude, but not sure if that's enough to make brute-force attempts feasible and non-destructive. (Also don't know the PNG format well enough to know if an image with the same pixels in it is guaranteed to produce the same bytes in the file across different implementations) -- [[User:Angel|Angel]] ([[User talk:Angel|talk]]) 11:16, 14 January 2022 (UTC)
:::::Hmm… if it was pure black and white, the total number of possible images would be within the realms of sanity to brute force. But add antialiasing and the numbers rapidly become silly. Even if you only allow pixels to change within a certain distance of the previous image, and restrict greys to places between a black and a white, the numbers quickly become absurd. Although that makes me think about making 1-bit versions of all the images so far, predicting a set of "next frame" possibilities at each step, and training a CNN to pick the correct next one; and if it gets accurate enough by the time we get to the present… hmm. How predictable is antialiasing? Do we know the software he's using to create the images; and if so is there a relatively predictable algorithm applied along the edges? [[User:Angel|Angel]] ([[User talk:Angel|talk]]) 11:41, 14 January 2022 (UTC)

I think it counts down to Lunar New Year (the Year of the Tiger), as measured in Korea (the earliest timezone where that is celebrated). Actually, it reaches 0 one minute before the New Year, so maybe it will switch to seconds for the last minute. [[Special:Contributions/172.70.98.75|172.70.98.75]] 05:10, 12 January 2022 (UTC)
:Could be, but why. Randall has never to rarely? mentioned this new year... --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 11:13, 12 January 2022 (UTC)

I think we are seeing a zoom out of some image. Perhaps it is the arm of Cueball? --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 11:36, 12 January 2022 (UTC)
:It looks like there's a little curve at the top left of the line entering the frame! This makes the Cueball arm hypothesis more likely. [[User:Sure|Sure]] ([[User talk:Sure|talk]]) 14:18, 12 January 2022 (UTC)
::I also noticed that (and moved your comment up here, as it is kind of a reply to that). Seems like the picture updates every four hours, and that it happened last time at noon UTC today. And thus it will also be at midnight. So 4, 8, 12, 16, 20 and 24. But it is not certain yet and not sure it happened like that the first day or two. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 14:46, 12 January 2022 (UTC)

I have added the first 12 images on this page: [[Countdown in header text/images]] - anyone may help uploading the new ones there. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 11:43, 12 January 2022 (UTC)
: Thank you! [[Special:Contributions/173.245.52.194|173.245.52.194]] 12:44, 12 January 2022 (UTC)

Does anyone mind if I make a few spelling/grammar corrections to the article? It feels like the kind of thing that could be interpreted as rude, so I wanted to ask first. [[Special:Contributions/172.70.114.167|172.70.114.167]] 13:00, 12 January 2022 (UTC)
:No no please help me with my poor spelling. I'm Danish and not very good at spelling in English. Also anything I write is up for debate and can be changed. Just because I started this page do not give me ownership over it. As long as relevant info is not deleted the entire layout maybe changed. But better to get the page going sooner rather than later.--[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 14:46, 12 January 2022 (UTC)
::Alright!! Thank you so much for all your great work on this page! [[Special:Contributions/172.70.110.151|172.70.110.151]] 18:02, 13 January 2022 (UTC)

I originally put this (without realising it wasn't the Talk page) in the Images sub-page, in response to the revelation it was (very probably) the SHA256 of the image data that was used to name the file:
*When I first looked at it and decided it was an obvious hash (yes SHA256 sounds about right, but nice to know someone's tried it) I personally had hoped it would be a hash of the datetime (plus a salt, maybe, to give it that extra little frisson of difficulty in reverse engineering... ;) ). But if it's as you say I think I'll refrain from getting any rainbow-tables set up and bashing through the possibilities in the rather huge phase-space it could represent. Of course, there must be a look-up table used by the server. It'd be too much to hope for that it's publically exposed though, and totally a rookie-error if it is. (That Randall, and maybe anyone he actually drafted in to implement it to save himself the worry, is surely not going to commit.)
...anyway, bringing it here, as being more conversational than informative. Still thought I should say it, but stupidly long as a comment so maybe I needn't have repasted it again! [[Special:Contributions/172.70.85.79|172.70.85.79]] 03:39, 13 January 2022 (UTC)

(Put this in here as it was before in the explanation --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 12:02, 13 January 2022 (UTC):)
Was going to say it's Hangman, but it looks like it's zooming in on the diagonal instead of continuing to make a gibbet. [[User:Thisfox|Thisfox]] ([[User talk:Thisfox|talk]]) 06:37, 13 January 2022 (UTC)

I read the javascript of the countdown and noticed one thing that i didn't see mentioned anywhere on this page: the countdown text is moving upwards. When the countdown started the text was exactly in the middle of the image and at the end of the countdown the text will be at the top (you can see how it will look by changing the time in your system). The code will also make the text disappear and leave only the image after the countdown goes to zero. [[Special:Contributions/162.158.90.41|162.158.90.41]] 23:52, 13 January 2022 (UTC)
:Uuuh thanks that was interesting. Maybe to make more room for the image? --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 12:09, 14 January 2022 (UTC)

The Greensboro sit-ins started on Feb 1, though the time is different.. But black history month? {{unsigned ip|172.70.135.48}}

Thanks to [[User:Theusaf|Theusaf]] for helping with putting the images up on the image page. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 12:09, 14 January 2022 (UTC)

Anyone here that can make an animation out of the images and put it in the explanation? If it is "easy" could it be updated some times on the way towards the final image on January 31st... Like the one on [[Time]]. That would be really nice. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 17:02, 14 January 2022 (UTC)
:I made an animation: [https://imgur.com/a/INh77nL] (Now i realize it wasn't needed because there already is automatically updating animation linked from the page...) [[Special:Contributions/162.158.159.105|162.158.159.105]] 18:18, 15 January 2022 (UTC)

There's something else moving into the frame... We'll have to see what it is. [[User:Sure|Sure]] ([[User talk:Sure|talk]]) 19:12, 14 January 2022 (UTC)

To even find this page, I had to page backward through the comic to get to Decorative Constants, go to the discussion, and come across the link to this page from there. I suggest that there be a direct link to this page from the explanation of every comic that existed while the countdown was in progress. A second question: has anyone determined for sure whether the ‘camera’ is zooming out from a blank spot in the final image, in which case we can expect other stuff to come into view from above and right, OR is it panning onto an image that is not changing size, in which case nothing will appear except from the direction it’s moving toward? And if it’s panning, has anyone tried estimating where the current stuff will end up?[[Special:Contributions/108.162.246.76|108.162.246.76]] 07:42, 15 January 2022 (UTC)
:I agree with you and have now changed the four comics that was active while the count down was active so far, so the link to this page is above their explanations. If people keep updating like this for new comics, there will be a link to the countdown page from the [https://www.explainxkcd.com/wiki/index.php/Main_Page front page]. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 14:40, 15 January 2022 (UTC)

Does Randall already have kids? If not, maybe his wife is expecting? That's something you'd announce and the last two comics are about kids. Another idea: he's going to space 🚀. --[[Special:Contributions/162.158.233.115|162.158.233.115]] 20:47, 15 January 2022 (UTC)
:I’m sure he would have a birth announcement afterward, but I doubt he would try to predict it to the exact second, 21 days in advance.[[Special:Contributions/162.158.106.105|162.158.106.105]] 22:36, 15 January 2022 (UTC)

I noticed that it almost appears to be the tail fin of an airplane. I don’t know if it is, or if an airplane even makes sense? --[[Special:Contributions/172.70.230.57|172.70.230.57]] 22:11, 15 January 2022 (UTC)

2549: Edge Cake

2021-12-02T04:25:11Z

162.158.106.105: /* Explanation */

{{comic
| number = 2549
| date = December 1, 2021
| title = Edge Cake
| image = edge_cake.png
| titletext = Every time IERS adds or removes a leap second, they send me a birthday cake out of superstition.
}}

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

[[Megan]] wishes Emily, represented as [[Hairbun]], Happy Birthday, prompting a confused [[Cueball]], as Emily probably told him that her birthday was sometime last month. Emily explains that she was born over the North Pole in a plane, meaning that she was born in every timezone at once. She also says that it was February 29th. February 29th only happens once every four years, because of leap years, adding to the confusion - people born on February 29th often celebrate their non-leap-year birthdays on arbitrary days. Also, the airplane was changing ownership from one country to another at the time, so any attempt to use the airplane owner's timezone would not work.

The title text states that the {{w|IERS}} sends Emily a cake every time they add or remove a leap second, out of superstition. The International Earth Rotation and Reference Systems Service is in charge of global time standards.

The comic title is a pun on {{w|Edge_case}}, an engineering term referring to extreme situations or conditions.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
[Megan is walking towards Cueball and Emily (who resembles Hairbun), holding a cake.]
:Megan: Happy birthday, Emily!
:Cueball: Wait, wasn't that last month? When's your birthday, anyways?
:Emily: It's complicated.

[A diagram of a flight path over the North Pole, with meridian lines radiating out from the center. Emily's dialogue appears above the diagram, but she herself does not appear in this panel.]
:Emily: My mom went into labor on an arctic international flight that diverted directly over the North Pole.
:Emily: I was born in every time zone at once.

[With Megan standing behind her, Emily holds out a plate of cake to Cueball.]
:Emily: It was also February 29th, and the airline was just changing ownership between countries.
:Emily: The International Bureau of Weights and Measures finally issued a declaration that it's my birthday whenever I want.
:Emily: Cake?
:Cueball: Nice, it's all edge pieces.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Hairbun]]

2549: Edge Cake

2021-12-02T04:23:55Z

162.158.106.105: /* Explanation */

{{comic
| number = 2549
| date = December 1, 2021
| title = Edge Cake
| image = edge_cake.png
| titletext = Every time IERS adds or removes a leap second, they send me a birthday cake out of superstition.
}}

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

[[Megan]] wishes Emily, represented as [[Hairbun]], Happy Birthday, prompting a confused [[Cueball]], as Emily probably told him that her birthday was sometime last month. Emily explains that she was born over the North Pole in a plane, meaning that she was born in every timezone at once. She also says that it was February 29th. February 29th only happens once every four years, because of leap years, adding to the confusion - people born on February 29th often celebrate their non-leap-year birthdays on arbitrary days. Also, the airplane was changing ownership from one country to another at the time, so any attempt to use the airplane owner's timezone would not work.

The title text states that the {{w|IERS}} sends Emily a cake every time they add or remove a leap second, out of superstition. The International Earth Rotation and Reference Systems Service is in charge of global time standards.

The comic title is a pun on {{w|Edge_Case}}, an engineering term referring to extreme situations or conditions.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
[Megan is walking towards Cueball and Emily (who resembles Hairbun), holding a cake.]
:Megan: Happy birthday, Emily!
:Cueball: Wait, wasn't that last month? When's your birthday, anyways?
:Emily: It's complicated.

[A diagram of a flight path over the North Pole, with meridian lines radiating out from the center. Emily's dialogue appears above the diagram, but she herself does not appear in this panel.]
:Emily: My mom went into labor on an arctic international flight that diverted directly over the North Pole.
:Emily: I was born in every time zone at once.

[With Megan standing behind her, Emily holds out a plate of cake to Cueball.]
:Emily: It was also February 29th, and the airline was just changing ownership between countries.
:Emily: The International Bureau of Weights and Measures finally issued a declaration that it's my birthday whenever I want.
:Emily: Cake?
:Cueball: Nice, it's all edge pieces.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Hairbun]]

2549: Edge Cake

2021-12-02T04:22:46Z

162.158.106.105:

{{comic
| number = 2549
| date = December 1, 2021
| title = Edge Cake
| image = edge_cake.png
| titletext = Every time IERS adds or removes a leap second, they send me a birthday cake out of superstition.
}}

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

[[Megan]] wishes Emily, represented as [[Hairbun]], Happy Birthday, prompting a confused [[Cueball]], as Emily probably told him that her birthday was sometime last month. Emily explains that she was born over the North Pole in a plane, meaning that she was born in every timezone at once. She also says that it was February 29th. February 29th only happens once every four years, because of leap years, adding to the confusion - people born on February 29th often celebrate their non-leap-year birthdays on arbitrary days. Also, the airplane was changing ownership from one country to another at the time, so any attempt to use the airplane owner's timezone would not work.

The title text states that the {{w|IERS}} sends Emily a cake every time they add or remove a leap second, out of superstition. The International Earth Rotation and Reference Systems Service is in charge of global time standards.

The comic title is a pun on {{w|Edge Case}}, an engineering term referring to extreme situations or conditions.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
[Megan is walking towards Cueball and Emily (who resembles Hairbun), holding a cake.]
:Megan: Happy birthday, Emily!
:Cueball: Wait, wasn't that last month? When's your birthday, anyways?
:Emily: It's complicated.

[A diagram of a flight path over the North Pole, with meridian lines radiating out from the center. Emily's dialogue appears above the diagram, but she herself does not appear in this panel.]
:Emily: My mom went into labor on an arctic international flight that diverted directly over the North Pole.
:Emily: I was born in every time zone at once.

[With Megan standing behind her, Emily holds out a plate of cake to Cueball.]
:Emily: It was also February 29th, and the airline was just changing ownership between countries.
:Emily: The International Bureau of Weights and Measures finally issued a declaration that it's my birthday whenever I want.
:Emily: Cake?
:Cueball: Nice, it's all edge pieces.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Hairbun]]

Talk:121: Balloon

2021-11-24T00:36:41Z

162.158.106.105:

From the wording of the comic, I think this is a reference to a film or a TV show.{{unsigned ip|120.148.234.14}}

[[Special:Contributions/72.193.171.120|72.193.171.120]] 00:40, 23 September 2013 (UTC) I thought it was a reference to a scene from the French Film, The Red Balloon, but I couldn't find a full movie where I could watch it for free without signing up for something. If there's a restaurant scene in that movie, that might be my guess.[[Special:Contributions/72.193.171.120|72.193.171.120]] 00:40, 23 September 2013 (UTC)

The title text could be a reference to the pilot episode of Firefly where Mal says, "I am a bad man" after tormented Simon for fun. --[[Special:Contributions/160.5.148.8|160.5.148.8]] 07:25, 24 October 2013 (UTC)

The balloon never goes inside in the movie [http://en.wikipedia.org/wiki/The_Red_Balloon The Red Balloon].[[User:Adamaustin|-adamaustin]] ([[User talk:Adamaustin|talk]]) 16:39, 13 November 2013 (UTC)

I think the first comment here was wondering if "The Restaurant" is the name of any piece of work. Mainly because that's whati was wondering, though. :) [[Special:Contributions/108.162.208.23|108.162.208.23]] 18:31, 25 January 2016 (UTC)

I could be wrong, but I don’t think most ceiling fans or balloon strings are strong enough to lift any child that size. I’m not sure what would happen, though, and it almost certainly depends on how securely the child is holding the balloon. [[Special:Contributions/162.158.62.249|162.158.62.249]] 06:16, 20 December 2016 (UTC)

This is a kid, thus not Cueball. I have removed that category. Should there be a category with comics featuring kids? --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 20:31, 10 October 2019 (UTC)
:Yes, I think it would be an interesting compilation. [[:Category:Comics featuring Science Girl]] should be a subcategory. From the top of my head, I would name in addition to this one and the science girl ones: [[2208: Drone Fishing]], [[1753: Thumb War]], [[856: Trochee Fixation]], [[1548: 90s Kid]], [[1139: Rubber and Glue]], and most of the 1337-series, making it more than 5, enough for a category :) But I am sure there are more.

From looking this up, I have determined that this is probably from {{w|La La Land}}. I will need to watch it to find out though. [[User:Beanie|Beanie]] ([[User talk:Beanie|talk]]) 10:22, 10 December 2020 (UTC)
:Any progress on that? :P [[Special:Contributions/162.158.106.105|162.158.106.105]] 00:36, 24 November 2021 (UTC)

2520: Symbols

2021-11-17T05:06:11Z

162.158.106.105: "You're" is used in the comic, not "you are"

{{comic
| number = 2520
| date = September 24, 2021
| title = Symbols
| image = symbols.png
| titletext = "röntgen" and "rem" are 20th-century physics terms that mean "no trespassing."
}}

==Explanation==
{{incomplete|Created by VERY EXPENSIVE EQUIPMENT - Please change this comment when editing this page. Do NOT delete this tag too soon. Bare-bones explanation is in, but needs much more detail.}}

This comic refers to elements of (mostly mathematical or engineering) notation commonly used in various fields of math and science. Each piece of notation is presented as "symbolizing" not what it specifically means, but a typical ''context'' in which it might be encountered. Many of the individual descriptions look like verbiage that might be found on informational or warnings signs or placards, although typically with a silly edge.

*d⁄dx: An undergrad is working very hard
d/dx is the symbol for a single-variable {{w|Derivative|derivative}}. This is one of the basic operations in {{w|calculus}} and consequently is ubiquitous in the work of undergraduates in the sciences. A hard-working undergraduate in the relevant fields would churn through exercises using this symbol.

*∂⁄∂x: A grad student is working very hard
The replacement of the standard "d" letters with the curly letters "∂" denotes the partial derivative, which generalizes the ordinary derivative to multi-variable calculus. Problems with partial derivatives, especially partial differential equations, can be extremely challenging. Although PDEs would typically be first taught at an undergraduate level, difficult partial derivatives would be encountered in graduate-level work.

*ħ: Oh wow, this is apparently a quantum thing
ħ (pronounced "h-bar") is a symbol used for (the reduced) {{w|Planck's constant}}, a universal, fundamental constant in quantum physics. ħ is equal to the energy of a photon divided by its frequency, and angular momentum in quantum mechanical systems is measured in quantized integer or half-integer units of ħ.
Classical physics appears as a limit of quantum physics if all "actions" (quantities of dimension energy * time, momentum * length, or angular momentum) are much larger than ħ. Conversely you can also formally set ħ=0 to get classical results from quantum formulae. This means that effects which are proportional to some power of ħ cannot be explained classically, and instead are "a quantum thing".

*Rₑ: Someone needs to do a lot of tedious numerical work; hopefully it's not you
The {{w|Reynolds number}} (which is actually usually denoted by "Re," not "Re" as it appears in the comic) is the most important dimensionless group in fluid mechanics. Named for Osborne Reynolds, Re characterizes the relative sizes of inertial and viscous effects in a moving fluid. Large values of Re are indicative of turbulent flow, which cannot usually be solved for analytically, and so numerical modeling is necessary. Accurate numerical studies of high-Reynolds-number flows are notoriously difficult to create and program.

Alternatively, Rₑ could stand for electronic {{w|transition dipole moment}} in a molecule. This appears in quantum-mechanical calculations of transition probabilities and also includes a lot of unpleasant numerical work. Rₑ is also a term used for the radius of the Earth at mean sea level, though this is not necessarily a complex term in and of itself.

Another alternative is that Rₑ could refer to Relative Error, a measurement of precision or accuracy. Used often in the analysis of scientific data and in numerical analysis.

*(Ta⁴ - Tb⁴): You are at risk of skin burns
The {{w|Stefan-Boltzmann law}} says that a perfectly absorbing ("black body") source emits electromagnetic radiation with a power per unit area of σT4, where σ is a known constant and T is the absolute temperature. The quantity (Ta4 – Tb4) thus appears in any calculation of purely radiative energy transfer between two bodies, one at temperature Ta and the other at Tb. When radiative transfer is large enough to be the most important form of heat interchange, it is normally also large enough to sear the skin with thermal or ultraviolet burns.

*NA: You are probably about to make an incredibly dangerous arithmetic error
NA, or {{w|Avogadro's number}}, is the number of molecules in a mole of a substance—roughly the number of protons plus neutrons in 12 gram of carbon-12. This is an enormous number, exactly 6.022 140 76 × 10²³, or 602 214 076 000 000 000 000 000. Adding up molecular weights and converting between grams and moles of several substances is a lot of arithmetic on a scale where intuition won't help you catch mistakes. Working with NA, it is easy to make errors of one or more powers of ten without noticing. If this kind of error is made in the calculation of the stoichiometrically correct amount of a reagent in a chemical reaction, it is possible to accidentally create dangerous amounts of unwanted chemical products.

*µm: Careful, that equipment is expensive
{{w|Micrometre|Micrometer}}s are a very small unit of distance. Micrometers are commonly used to measure wavelengths in the infrared, and infrared detectors are very expensive, compared with visible wavelength counterparts. Of course, micrometers are used as a measurement of distance in other contexts, but any distance-measuring device capable of accurately measuring micrometer distances would also be expensive. Similarly, tools used to create or calibrate items within micrometer tolerances can also be expensive.

*mK: Careful, that equipment is very expensive
{{w|Kelvin}} is a temperature scale roughly speaking similar to Celsius, but taking absolute zero as its zero point instead of the freezing point of water (rigorously speaking, its definition is now {{w|2019_redefinition_of_the_SI_base_units#Kelvin|based on the Boltzmann constant}}). {{w|Millikelvin}}s (1/1000 of a Kelvin) are used for high precision temperature work. Frequently this is used in processes of cooling temperatures to near absolute zero - such as superconductors or other quantum effects that occur when atoms are almost still. This is suggesting that the symbol appears on a sensitive experimental system probing quantum mechanical behavior that would likely only exist in an advanced laboratory. Any equipment that works down at mK temperatures, or at least to mK precision and accuracy, is likely to be very expensive.

*nm: Don't shine that in your eye
{{w|Nanometer}}s are frequently seen in the listed wavelengths for lasers. Pointing a visible or infrared laser at someone's eye is notoriously dangerous; the tightly-focused coherent light can cause permanent damage very quickly.

*eV: Definitely don't shine that in your eye
{{w|Electron volt}} energies are typical of moderate-energy particle beams, produced by accelerating electrons (or protons) over macroscopic voltages. These particle beams can be {{w|Anatoli Bugorski|even more damaging (and are probably a direct reference to Anatoli Bugorski)}} to soft tissues than optical-wavelength lasers.

*mSv: You're about to get into an Internet argument
The {{w|millisievert}} is a unit of radiation dose absorbed. It is actually a very small dosage, but the joke refers to Internet trolls debating the effects of low-dose radiation sources, such as 5G wireless networks. [[Randall|Randall's]] comment may also be referring to [https://xkcd.com/radiation/ this chart].

*mg/kg: Go wash your hands
This unit measures the dose of a drug or other chemical in milligrams per kilogram of body mass. If the appropriate dose - or worse, the lethal dose - is measured in mg/kg (parts per million), then the substance may be quite toxic.

*µg/kg: Go get in the chemical shower
A unit 1/1000 times the size of mg/kg. If a dosage is measured in micrograms per kilogram (parts per billion), any accident probably requires whole-body decontamination procedures.

*π or τ: Whatever answer you get will be wrong by a factor of exactly two
π is defined as the ratio of a circle's circumference to its diameter, while τ is defined as the ratio of a circle's circumference to its radius (and is therefore equal to 2π). {{w|pi|π}} has been used as the primary constant for describing the circumference and area of circles for millennia, but proponents of {{w|Turn (angle)|τ}} claim that τ is actually more natural in most contexts, since it makes working in radians more straightforward. The joke here is that whichever constant you use, it will probably be the wrong one (off by a factor of two, one way or the other) for the formula you are trying to use. The debate over Tau vs Pi was solved by Randall in this compromise: [[1292: Pi vs. Tau]].

The title text refers to two non-SI units of radiation measurement, {{w|Roentgen (unit)|röntgen}} and {{w|Roentgen equivalent man|rem}}. In the mid-20th century when they were in use, the dangers of radiation weren't as well understood as today, so an area with radiation that was noteworthy back then is probably dangerous[https://archive.md/v3dME], hence the no trespassing part.

==Transcript==
:[A list with 14 different scientific constants/symbols are shown. Next to each symbol is a description. Above the list is a heading and beneath that a subheading.]
:::::<big>Symbols</big>
::::And what they mean

:::d⁄dx    An undergrad is working very hard
:::∂⁄∂x    A grad student is working very hard
:::ħ       Oh wow, this is apparently a quantum thing
:::Rₑ     Someone needs to do a lot of tedious numerical work; hopefully it's not you
:(Ta⁴ - Tb⁴)    You are at risk of skin burns
:::NA    You are probably about to make an incredibly dangerous arithmetic error
:::µm    Careful, that equipment is expensive
:::mK    Careful, that equipment is very expensive
:::nm    Don't shine that in your eye
:::eV     '''''Definitely''''' don't shine that in your eye
:::mSv  You're about to get into an internet argument
::mg/kg      Go wash your hands
::µg/kg      Go get in the chemical shower
::π or τ      Whatever answer you get will be wrong by a factor of exactly two

{{comic discussion}}

[[Category:Math]]
[[Category:Physics]]
[[Category:Chemistry]]
[[Category:Biology]]
[[Category:5G]]

1028: Communication

2021-11-17T01:22:35Z

162.158.106.105:

{{comic
| number = 1028
| date = March 12, 2012
| title = Communication
| image = communication.png
| titletext = Anyone who says that they're great at communicating but 'people are bad at listening' is confused about how communication works.
}}

==Explanation==
This comic is divided into two parts, the first two rows of panels and then the third one.

The first part demonstrates a failed attempt at communication:

*[[White Hat]] notices a dangerous hole, and thinks he should warn people about it.
**The symbol of the triangle with the exclamation mark in it (⚠) is widely used on {{w|warning signs}} and it means "{{w|Warning_sign#General_caution|General caution}}".
*White Hat encounters [[Hairy]] and tries to warn him about the hole, while Hairy thinks White Hat is being over-dramatic and doesn’t heed his caution.
*Hairy doesn't understand the warning, he continues to think without speaking. Now he thinks of a frustrated White Hat.
*Hairy continues to only think of what he can see, and now this is the fact that White Hat is leaving. As White Hat leaves he is thinking about Hairy's lack of understanding and about his silence.
*White Hat encounters [[Megan]] and is now so annoyed about Hairy that he rather talks about his lack of communication than about the dangerous hole. Megan on the other hand tries to tell White Hat about another dangerous hole if he continues to walk along.
*White Hat and Megan pass each other. White Hat now thinks about both the silent Hairy and the talking Megan who both failed to understand him. Megan is just frustrated by the outcome of her encounter and thinks about White Hat talking.
*Megan then meets Hairy while they are both still thinking about White Hat
*They now share their common experience of seeing White Hat. Finally Hairy talks.
*They both continue towards the first hole, unaware of it, talking about White Hat. (Hairy is drawn without hair both here and in the next panel - see [[#Trivia|Trivia]] below.)
*Megan and Hairy fall into the first hole since it wasn't properly communicated to them.
*White Hat falls into the second hole since it wasn't properly communicated to him.

The holes in the sidewalk are fairly deep, about one person deep; unaware and careless people don't notice them when they come upon them, which makes them symbolic of any problem or danger one can encounter in life, and could avoid if properly warned or careful.

The second part demonstrates a much more successful attempt at communication:

*[[Beret Guy]] notices a dangerous hole, and thinks he should warn people about it.
*He even runs out of the picture to warn people (as can be interpreted by the fact that he has reached further in the next panel than White Hat).
*Beret Guy finds [[Cueball]], and tells him to come along. Cueball only sees Beret Guy stretching out his hand.
*Beret Guy takes Cueball's hand and leads him towards the hole. Cueball doesn't understand why (as shown by the question marks in his thought bubble surrounding his thought of Beret Guy), but follows Beret Guy anyway.
*Beret Guy leads Cueball to the hole and points it out for him.
*Finally both Beret Guy and Cueball leave the hole thinking about the danger of it. Beret Guy has managed to properly warn Cueball about the hole.

The title text references the requirement that "communication" is a two-sided process, and just because you think you have made your point clear this does not mean that you have "communicated" the information to them: if they failed to understand, then it may as well mean that ''you'' failed to communicate, and not necessarily that ''they'' are bad at listening. And if you always encounter this situation, then it is you who are confused about how communication works. See also [[1984: Misinterpretation]].

==Transcript==
:[White Hat looks down at a large gap in the walkway; a thought bubble with a warning symbol and an image of the gap appears above his head.]

:[White Hat walks to the right, away from the gap, and encounters Hairy, to which he speaks (in iconographic speech bubble form) while pointing toward the gap, attempting to inform him about the gap. A thought bubble appears above Hairy's head with an image of White Hat pointing.]

:[White Hat continues, waving his arms, still talking about the gap. Hairy's thought bubble continues to contain images of White Hat, now gesturing frantically.]

:[Hairy shrugs in a nonplussed manner, and White Hat leaves off the right side of the frame. Both have thought bubbles displaying the other's reaction.]

:[White Hat continues to the right and comes across Megan. He tells her about the reaction of Hairy (still all in iconographic form); she simultaneously tries to tell him about a gap and gestures off to the right of the frame.]

:[White Hat and Megan both leave the frame. Megan exits left thinking of White Hat's reactions; White Hat exits to the right while thinking about both Hairy and Megan's reactions.]

:[Megan (still thinking about White Hat) encounters Hairy (who is also still thinking about White Hat).]

:[Megan and Hairy talk about White Hat.]

:[Megan and Hairy (now without his hair) continue talking about White Hat as they exit the frame to the left.]

:[A commotion is heard from the left.]
:Explosion to the left: !!! ** !!

:[Megan and Hairy (still without his hair) have fallen into the gap in the walkway. A commotion is then also heard from the right.]
:Explosion to the right: !!! ** *

:[White Hat has fallen into another gap.]

:[Beret Guy looks down at a large gap in the walkway; a thought bubble with a warning symbol and an image of the gap appears above his head.]

:[Beret Guy runs off the frame to the right.]

:[Beret Guy meets Cueball and reaches out to him. He tells him (still in iconographic form) that Cueball should take Beret Guy's hand. Cueball has a thought bubble of Beret Guy with his arm stretched out.]

:[Beret Guy takes Cueball's hand and leads him along to the left. Cueball's thought bubble has two question marks around Beret Guy.]
:Cueball: ? ?

:[Beret Guy leads Cueball to the gap and points it out to him.]

:[Beret Guy and Cueball walk away from the gap to the right, now both thinking about the gap with a warning symbol above it.]

==Trivia==
[[Randall]] made a mistake in this comic: Hairy seems to "lose" his hair in the last two frames where he is together with Megan (#9 and #11), but it's still the same person. The Cueball that appears in the last four frames represents another person. This is clearly evidenced by Randall's [http://xkcd.com/1028/info.0.json transcript of the comic].

{{comic discussion}}

[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Hairy]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Beret Guy]]
[[Category:Comics featuring Cueball]]
[[Category:Social interactions]]

Talk:2534: Retractable Rocket

2021-10-28T09:13:00Z

162.158.106.105:

However it is done, note that the base of the 'first stage' extends/retracts in advance of the bit further up, as can be seen by the panelling position in the standing/extending/extended/retracted frame-sequence. Which might be worth noting if you're wanting to copy the technology. [[Special:Contributions/172.70.85.185|172.70.85.185]] 03:09, 28 October 2021 (UTC)

: I think this might be theoretically possible, ignoring the apparently topological outer skin of the "rocket", with some kind of steerable [https://en.wikipedia.org/wiki/Space_fountain space fountain]. Accelerating the astronauts at 10g for about two minutes might be survivable, and could limit the overall length to just over 800 miles. Though the shroud only has to extend to where the atmosphere is "sufficiently" thin. No idea whether this kind of design would tend to fall over when finished or not. -- [[User:Ken g6|Ken g6]] ([[User talk:Ken g6|talk]]) 04:24, 28 October 2021 (UTC)
::I believe it is 100% impossible. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 07:45, 28 October 2021 (UTC)

If (as it appears) the Bot created the page with various references to "Retract'''i'''ble" rarher than "Retract'''a'''ble", does this mean Randall made that error initially? (I say this as the guy who failed to notice he'd put "re'''su'''able" in his Transcript edit. ;) ) [[Special:Contributions/172.70.162.129|172.70.162.129]] 03:54, 28 October 2021 (UTC)

: Looks like yep, Randall originally made that error persistently, as the image here still has "retractible" in the comic, but the image on xkcd.com has been updated. Not sure how this is usually handled, I think it's mentioned in the FAQ.
: Edit: okay, I've uploaded the new image, and added a trivia bit about the original. No idea how to update the page URL, that'll have to be someone else. [[User:Esogalt|Esogalt]] ([[User talk:Esogalt|talk]]) 04:02, 28 October 2021 (UTC)

In my own opinion I think this is actually a brilliant idea, if you think outside the box. Imagine those floppy noodle blow up baloons they use at car dealerships and the like. Now replace the continuous membrane with a membrane combined with multiple stages of internal baffles that can collapse and move around vertically, and scale the whole thing up. Now think about a straw. What if we engineered a straw that reaches all the way to the target (and then back into the atmosphere), and inflate it? we could have [https://en.wikipedia.org/wiki/ThothX_Tower] the ThothX tower but that is a stacked kevlar cell system that only reaches 12 miles in height. The weight is not truly supported by the air, but rather by the tensile strength of the membranes. The question is how much air we'd need to move and how big would it need to be to function. [[Special:Contributions/172.69.69.182|172.69.69.182]] 04:45, 28 October 2021 (UTC)

Is there a compelling reason to refer to the countdown as spoken by "Tannoy" rather than "PA" or "Loudspeaker" or something? I had to look up what that was. [[User:Esogalt|Esogalt]] ([[User talk:Esogalt|talk]]) 05:09, 28 October 2021 (UTC)
:I have correct to a count down voice. We have no idea how it emanates. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 07:44, 28 October 2021 (UTC)

I tried to update the page and image URLs to fix the misspelling, and I think it mostly worked. But if you click the "Next" button from the previous comic it doesn't work so smoothly. Anyone know how to fix that?? [[User:Orion205|Orion205]] ([[User talk:Orion205|talk]]) 05:40, 28 October 2021 (UTC)
: <strike>Erm, this seems to have broken the main page as well. I've found [[https://www.mediawiki.org/wiki/Special:MyLanguage/Help:Moving_a_page]], which says to use the "Move" option in the "More" menu at the top of the page. Did you use that?</strike> Never mind, I think I was just the victim of cache weirdness. [[User:Esogalt|Esogalt]] ([[User talk:Esogalt|talk]]) 05:51, 28 October 2021 (UTC)

As a rule, when you’re correcting someone else’s mistake, proofread your correction, or you might make a new mistake that will leave “it is” mark on explainxkcd. [[Special:Contributions/162.158.106.105|162.158.106.105]] 09:13, 28 October 2021 (UTC)

2531: Dark Arts

2021-10-21T17:16:32Z

162.158.106.105: /* Explanation */ changed hardlink to a more insidious example

{{comic
| number = 2531
| date = October 20, 2021
| title = Dark Arts
| image = dark_arts.png
| titletext = You think, 'okay, THIS is an ideal use case for hardlinks!' but then 6 months later you're doing some extremely cursed Google search like 'javascript ext4' and wondering where things went wrong.
}}

==Explanation==
{{incomplete|Created by a V8-BASED EXT4 FUSE DRIVER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

In this comic, [[White Hat]] has presumably just asked [[Cueball]] to perform some task involving {{w|file system|filesystems}}. Cueball responds to this request with an extremely melodramatic monologue, referring to knowledge of the subject as "dark arts" and stating he'd rather not have anything to do with them, as they are too dangerous.

This reaction is reminiscent of a fairly typical scene in e.g. superhero movies, where a person with supernatural powers explains they prefer not to use them, as their use is likely to have negative effects that outweigh the positive ones. Often this is tied to a tragic backstory of the character, where the use of their powers previously caused them or someone close to them much pain and suffering.

A filesystem is the part of a computer's {{w|operating system}} that handles the organisation of data in persistent storage, usually splitting it into files and directories. It can be a very complicated piece of software. Because of this, it is very easy to make mistakes when interacting with it outside of the most common operations most users would be familiar with, and because it controls practically all of a user's data on a given machine, mistakes made can have very serious consequences (e.g., loss of data). This is probably why Cueball is reluctant to mess with them.

{{w|ext4}} is a popular filesystem used with the {{w|Linux}} operating system kernel.

{{w|hard_link|Hardlinks}}, allow two filenames to refer to the same underlying file or directory. These can be particularly tricky to use, as in nearly all respects they look like regular files, but modifying them can have effects that are not immediately obvious (e.g., if you changing what one filename refers to, the other will not remain consistent). Hardlinks and their misuse have been referenced in xkcd before, as in [[981: Porn Folder]].

The title text hints at an experience Cueball or [[Randall]] has had in the past (his own "tragic backstory", if you will), involving hardlinks on ext4. He thought he had found an ideal use case for them, one which presumably avoided most of their pitfalls, but still, 6 months later, ends up having to troubleshoot some inscrutable bug arising from his decision.

{{w|Javascript}} is a programming language most often associated with web pages. Because of this it is not usually interacting directly with a computer's filesystem, as allowing arbitrary websites to access the filesystem is widely considered an extremely bad idea{{citation needed}}, from a security standpoint. It ''is'' possible to run Javascript directly outside of a browser -- in which case it does have access to common filesystem operations, and even theoretically to the internals of the filesystem -- but since it is a high-level language with poor support for working with the data structures a filesystem uses, this would be a painful, "cursed" way to go about things.

An experienced IT professional will be reminded of their own experiences and mishaps with non trivial file system configurations. Beyond hardlinks, fileystems may have a number of features a normal user or even an admin are not aware of. Such features are prone to bugs, poor documentation or poor integration with other system tools.
For example:
* {{w|Symbolic link|Symbolic links}} (soft links) - one file links to another using its name. While symbolic links work "everywhere," hardlinks are generally limited.
* Compressed filesystems can cause unexpected side effects in performance, quota management and disk fragmentation.
* Sparse files and shallow copies (copy on demand).
* Live filesystem backup and file locking.
* Read only filesystems.
* 'Virtual' filesystems, like memory backed and file backed file systems, backed by dynamic data or databases.
* 'Overlay' file systems where a read only portion is overlayed and partially shadowed by another file system.
* File caching for read or write operation.
* Syncing file systems.
* Many, many more.

"In another age" might refer to the fact that these kinds of detailed manipulations (and forgetting about them six months later) were common in the days before containers, immutable server pattern, serverless, etc. In fact, one of the goals of these more modern deployment methods is to AVOID this kind of detailed maintenance. Today, for example, the exact structure of a Docker image can be determined by looking at the Dockerfile. Even configuration tools like Chef and Ansible help, because they provide Infrastructure as Code and you can look at the code to see what kinds of manipulations need to be done (vs. forgetting that time way back when that you did them manually).

==Transcript==
:[Cueball and White Hat stand in a slightly darkened room, with a jagged circle of light centered on Cueball emanating from the floor and light reflecting onto White Hat's face. Cueball holds his arm out with his palm facing towards White Hat.]
:Cueball: Long ago, in another age, I mastered these dark arts.
:Cueball: But I now endeavor to live my life such that I never need them.
:Cueball: Their power leads only to ruin.
:[Caption below panel]
:My response whenever anyone asks me to mess around with filesystems

{{comic discussion}}
[[Category: Comics featuring Cueball]]
[[Category: Comics featuring White Hat]]
[[Category: Computers]]

2531: Dark Arts

2021-10-21T17:09:14Z

162.158.106.105: /* Explanation */ symbolic links - add symbolic link to wikipedia, also brief what it is

{{comic
| number = 2531
| date = October 20, 2021
| title = Dark Arts
| image = dark_arts.png
| titletext = You think, 'okay, THIS is an ideal use case for hardlinks!' but then 6 months later you're doing some extremely cursed Google search like 'javascript ext4' and wondering where things went wrong.
}}

==Explanation==
{{incomplete|Created by a V8-BASED EXT4 FUSE DRIVER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

In this comic, [[White Hat]] has presumably just asked [[Cueball]] to perform some task involving {{w|file system|filesystems}}. Cueball responds to this request with an extremely melodramatic monologue, referring to knowledge of the subject as "dark arts" and stating he'd rather not have anything to do with them, as they are too dangerous.

This reaction is reminiscent of a fairly typical scene in e.g. superhero movies, where a person with supernatural powers explains they prefer not to use them, as their use is likely to have negative effects that outweigh the positive ones. Often this is tied to a tragic backstory of the character, where the use of their powers previously caused them or someone close to them much pain and suffering.

A filesystem is the part of a computer's {{w|operating system}} that handles the organisation of data in persistent storage, usually splitting it into files and directories. It can be a very complicated piece of software. Because of this, it is very easy to make mistakes when interacting with it outside of the most common operations most users would be familiar with, and because it controls practically all of a user's data on a given machine, mistakes made can have very serious consequences (e.g., loss of data). This is probably why Cueball is reluctant to mess with them.

{{w|ext4}} is a popular filesystem used with the {{w|Linux}} operating system kernel.

{{w|hard_link|Hardlinks}}, allow two filenames to refer to the same underlying file. These can be particularly tricky to use, as in nearly all respects they look like regular files, but modifying them can have effects that are not immediately obvious (i.e., by changing the contents of another file). Hardlinks and their misuse have been referenced in xkcd before, as in [[981: Porn Folder]].

The title text hints at an experience Cueball or [[Randall]] has had in the past (his own "tragic backstory", if you will), involving hardlinks on ext4. He thought he had found an ideal use case for them, one which presumably avoided most of their pitfalls, but still, 6 months later, ends up having to troubleshoot some inscrutable bug arising from his decision.

{{w|Javascript}} is a programming language most often associated with web pages. Because of this it is not usually interacting directly with a computer's filesystem, as allowing arbitrary websites to access the filesystem is widely considered an extremely bad idea{{citation needed}}, from a security standpoint. It ''is'' possible to run Javascript directly outside of a browser -- in which case it does have access to common filesystem operations, and even theoretically to the internals of the filesystem -- but since it is a high-level language with poor support for working with the data structures a filesystem uses, this would be a painful, "cursed" way to go about things.

An experienced IT professional will be reminded of their own experiences and mishaps with non trivial file system configurations. Beyond hardlinks, fileystems may have a number of features a normal user or even an admin are not aware of. Such features are prone to bugs, poor documentation or poor integration with other system tools.
For example:
* {{w|Symbolic link|Symbolic links}} (soft links) - one file links to another using its name. While symbolic links work "everywhere," hardlinks are generally limited.
* Compressed filesystems can cause unexpected side effects in performance, quota management and disk fragmentation.
* Sparse files and shallow copies (copy on demand).
* Live filesystem backup and file locking.
* Read only filesystems.
* 'Virtual' filesystems, like memory backed and file backed file systems, backed by dynamic data or databases.
* 'Overlay' file systems where a read only portion is overlayed and partially shadowed by another file system.
* File caching for read or write operation.
* Syncing file systems.
* Many, many more.

"In another age" might refer to the fact that these kinds of detailed manipulations (and forgetting about them six months later) were common in the days before containers, immutable server pattern, serverless, etc. In fact, one of the goals of these more modern deployment methods is to AVOID this kind of detailed maintenance. Today, for example, the exact structure of a Docker image can be determined by looking at the Dockerfile. Even configuration tools like Chef and Ansible help, because they provide Infrastructure as Code and you can look at the code to see what kinds of manipulations need to be done (vs. forgetting that time way back when that you did them manually).

==Transcript==
:[Cueball and White Hat stand in a slightly darkened room, with a jagged circle of light centered on Cueball emanating from the floor and light reflecting onto White Hat's face. Cueball holds his arm out with his palm facing towards White Hat.]
:Cueball: Long ago, in another age, I mastered these dark arts.
:Cueball: But I now endeavor to live my life such that I never need them.
:Cueball: Their power leads only to ruin.
:[Caption below panel]
:My response whenever anyone asks me to mess around with filesystems

{{comic discussion}}
[[Category: Comics featuring Cueball]]
[[Category: Comics featuring White Hat]]
[[Category: Computers]]

2528: Flag Map Sabotage

2021-10-15T05:46:51Z

162.158.106.105:

{{comic
| number = 2528
| date = October 13, 2021
| title = Flag Map Sabotage
| image = flag_map_sabotage.png
| titletext = Delaware hopes to explore the western edge of areas marked with the Belgian flag, once the tornadoes die down.
}}

==Explanation==
{{incomplete|Created by a GOD-EMPEROR OF GREATER DELAWARE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

The comic refers to a type of map that colors countries using the national flag designs; see [https://i.pinimg.com/originals/41/0f/36/410f3661d1cee3b255b82a111f99d242.jpg here] for such a map of Europe. Randall proposes a new flag which is specifically designed to troll such maps. Most obviously, the flag includes its own legend, which uses multiple common flag colors to indicate random regional attributes. Hence, the mere act of placing this flag on a map would cause people to misinterpret this legend as applying to the entire map, given wildly false information about regions of other countries. This trick is reminiscent of [[327: Exploits of a Mom]], with Mrs. Robert's son <code>Robert'); DROP TABLE Students;--</code>.

In addition to the legend, the flag consists of two red fields, one of which has an irregular-shaped border, the other of which is a straight line. The irregular shape is similar to a geographical border based on natural features (such as rivers and coastlines), while borders which are not based on such features tend to be straight lines. Red is the most common color on national flags, so if any bordering country had red on their flag, it would risk bordering these red fields, confusing where the border lay (as well as designating the entire red region as "greater Delaware"). If this flag is intended for the USA (although the text mentions "our new country"), the red regions would be continuous with the red strips on both sides of Canada's flag and the red field on the right of Mexico's flag, disguising the border still further.

The title text refers to the flag of Belgium, which consists of three vertical stripes in the order (left to right) black, yellow, and red. The western part of Belgium would, according to the legend, be unexplored, while the eastern part would be Greater Delaware. The middle would therefore be a tornado zone separating the unexplored area from Greater Delaware. Depending on how the flags are aligned it might be possible to explore from the south, where the blue-white-red stripes of the French flag contain another piece of Greater Delaware that may be conveniently located to help said exploration. Exploring from the Netherlands (red, white, and blue horizontal stripes) is not viable as rebel forces are positioned between Greater Delaware and the unexplored region.

This is not the first time Randall has made a flag for a new country! See [[1815: Flag]]

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[A flag displays a white country-shaped area surrounded by a red field. Inside the shape sits a map legend.]

:Map Legend
:[Bright blue rectangle] Disputed territory
:[Green rectangle] Newly independent
:[Blue rectangle] Demilitarized zone
:[Yellow rectangle] Tornado warning
:[Dark blue rectangle] Held by rebel forces
:[Red rectangle] Greater Delaware
:[Black rectangle] Unexplored

:[Caption below panel]
:Our new country's flag sabotages those maps where geographic areas are colored in with flag patterns.

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Maps]]

667: SkiFree

2021-10-14T16:27:53Z

162.158.106.105: Fixed title text explanation, removing stuff that was clearly to deep.

{{comic
| number = 667
| date = November 25, 2009
| title = SkiFree
| image = skifree.png
| titletext = And from that day on, I wore this little 'F' key pendant everywhere I went.
}}

==Explanation==
''{{w|SkiFree}}'' is a video game released in 1991 which enjoyed popularity on the desktop computers of the time. In the game, you're a downhill skier who attempts to ski down a hill while avoiding obstacles which cause you to crash (which slows you down). At the start of the game, you can choose to go down three different timed/scored courses, or ignore them all and ski freely. Beyond the end of the courses you can continue skiing downhill. You can also move (slowly) uphill and sideways.

If you ski too far down the hill a monster similar to one in the comic will begin to chase you; contact with the monster ends the game. Since it's much faster than you normally, you'll get caught. The monster also appears if you travel too far in the sideways or upwards directions.

One of the lesser known commands in SkiFree is the 'F' key, which speeds you up, even faster than the monster. A second monster appears slightly further down the hill but by skiing downhill diagonally with the F key it is possible to evade both.

The joke here is that [[Megan]] has thought long and hard about the concept of the monster, relating it to the inevitability of death, and is nonplussed by the revelation that there is a simple mechanism that may allow her to escape it.

The title text refers to pendants or talismans that are worn to protect us from harm or to remind us of important truths. Meghan, seeing that the F key allowed her to evade inevitable death in the game, comes to believe that the F key confers some sort of immortality.

==Transcript==
:[A screenshot of SkiFree, with the abominable snowman running towards the player.]

:[Megan is sitting at her computer with her hands on the keyboard and thinking to herself:]
:Megan (thought bubble): I've always thought of the SkiFree monster as a metaphor for the inevitability of death.

:[Cueball comes up behind her in a frameless panel.]
:Cueball: SkiFree, huh? You know, you can press "F" to go faster than the monster and escape.

:[The screenshot again. The player is zooming away from the monster.]

:[Megan sits at her computer in silence, with her hands now down to to her side.]

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics with color]]
[[Category:Philosophy]]
[[Category:Video games]]

2520: Symbols

2021-09-24T21:18:10Z

162.158.106.105: /* Explanation */ Re-added title text explanation

2513: Saturn Hexagon

2021-09-11T03:07:36Z

162.158.106.105: /* Explanation */

{{comic
| number = 2513
| date = September 8, 2021
| title = Saturn Hexagon
| image = saturn_hexagon.png
| titletext = Sorry, in SI units that's "there's a big football in there."
}}

==Explanation==
{{incomplete|Created by CUEBALL'S POLAR HEXAGON - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
{{w|Saturn's Hexagon}} is a cloud formation on Saturn centered on its north pole. Similar to Jupiter's {{w|Great Red Spot}}, Saturn's Hexagon has proven a persistent feature observed by multiple space probes. The cause was not known until recently, when data from the 2006-2009 {{w|Cassini–Huygens}} probe could be analyzed in depth. This finding was widely publicized in popular science media (see for example [https://www.sciencealert.com/astronomers-think-they-figured-out-how-saturn-s-giant-hexagonal-storm-could-have-formed]) and is related to how currents flow deep within Saturn's atmosphere.

Randall proposes an alternate explanation: it is the top of a {{w|Ball_(association_football)|soccer ball}}. Soccer balls are made in the shape of a {{w|truncated icosahedron}}, where faces alternate between regular hexagons and regular pentagons to achieve a more uniform roll. This design was introduced in 1968 as the {{w|Adidas Telstar}}, and is now considered the "traditional" soccer ball.

Soccer is the name given in the United States to {{w|association football}}, a game called simply "football" in most of the world. Since a system derived from {{w|Imperial units}} of measurement (inches, feet, miles, pounds, etc.) is used in the United States whereas the SI/metric system (centimetres, metres, kilometres, kilograms, etc.) is the system in use in most of the world, "football" is jokingly referred to in the title text as the SI name for "soccer". As much of the Web panders to a significantly US-based audience{{fact}}, many sites use only Imperial-like measurements and omit metric equivalents, which might annoy non-US users; Randall parodies this by sarcastically and non-seriously apologizing.{{fact}}.

This comic may also reference something often quoted to students decades ago that Saturn [https://solarsystem.nasa.gov/planets/saturn/in-depth/#:~:text=Structure-,Structure,by%20intense%20pressure%20and%20heat. would float] if there were a large enough pool of water to hold it, often having been stated as "Saturn is a giant beach ball". This refers to the property that Saturn is the planet with the {{w|Saturn#Physical_characteristics|lowest average density}}. This, of course, is a lot more [https://www.wired.com/2013/07/no-saturn-wouldnt-float-in-water/ complicated] in reality.

The UK is the birthplace of association football and place of the origin of the term "soccer" — originally to {{w|Names_for_association_football#Background|distinguish it}} from rugby football (sometimes "rugger"), before soccer became the most common form of football. "Football" now means association football in Britain, as with most people on Earth. Other international variations will usually be identified explicitly, as with 'American' football (gridiron, or jocularly "hand-egg"), '{{w|Australian rules football|Aussie Rules}}' football and {{w|Gaelic}} football (outwith its own dedicated celtic 'homelands').

The UK is also a partial hold-out for imperial measures. Officially many everyday measurements must now be primarily given in their metric forms, if not more specifically SI, but in the UK and the US road distances remain signed in miles, with road-speeds in miles per hour; glasses of brewed alcohol and doorstep milk deliveries are in pints (indeed, it is ''illegal'' in the UK to sell draught beer or cider except as a ⅓ pint or multiple of ½ pint); feet-and-inches and stones-plus-pounds are still commonly used for a person's height and weight. (It's worth noting that the American pint is 16 fluid ounces or 473 ml whereas the Imperial pint is 20 fl.oz. or 568 ml.) As a further sop to those who still think better in 'old money' measures (an allusion to how British currency itself was non-decimal in nature until 1971), a weather presenter may add to their metric-based summary to also give temperatures in Fahrenheit and rainfall in inches (though windspeeds will all be in mph, or the {{w|Beaufort scale}} as used in the {{w|Shipping Forecast}}).

Incidentally, the presentation of the truncated-icosahedral 'football', pressing one clear polygonal face up along the upper limit of the planetary sphere, has much in common with the (non-truncated) icosahedron that floats within a {{w|Magic 8-Ball}}, arranged to display just one random triangular face whenever its viewing window is upwards. This may be coincidence, without any obvious attempt to directly reference any of the [https://knowyourmeme.com/photos/1404098-safely-endangered popular memes] relating to this. Randall has previously parodied the magic 8-ball in [[1525: Emojic 8 Ball]].

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

[Cueball is presenting in front of a poster, which he is pointing at with a stick.]

Cueball: We're proud to announce that our team has finally determined the origin and nature of Saturn's polar hexagon.

[The poster represents Saturn and its ring-system. There is a massive football/soccer ball drawn as if inside the semi-transparent planet, taking up slightly less than half of it by volume.
One of the ball's hexagons coincides with Saturn's polar hexagon, and is labelled "Hexagon". Other labels are illegible. 
The poster's title is "There's a Big Soccer Ball In There". The rest of the poster is illegible, except for a section heading that reads "BSBIT Model".]

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