explain xkcd - User contributions [en]

Talk:1114: Metallurgy

2023-07-03T20:53:40Z

XKCD Official: Replaced content with "Vandalised"

Vandalised

Talk:1588: Hardware Reductionism

2023-07-03T20:52:32Z

XKCD Official: Replaced content with "Vandalised"

Vandalised

Talk:1444: Cloud

2023-07-03T20:52:03Z

XKCD Official: Replaced content with "Vandalised"

Vandalised

Main Page/sandbox

2023-07-03T20:48:37Z

XKCD Official:

If you get to this vandalised sandbox page, say hi! —[[User:EnderPlays|EnderPlays]] October 11, 2022
:Hi —[[User:While False|While False]] ([[User:While False/explain xkcd museum|'''museum''']] | [[User talk:While False|talk]] | [[special:Contributions/While_False|contributions]] | [[special:Log/While_False|logs]] | [[Special:UserRights/While_False|rights]]) {{CURRENTTIME}}, {{CURRENTDAY}} {{CURRENTMONTHNAME}} {{CURRENTYEAR}} (UTC)
:Hi
:Hi! [[User:Netherin5|“That Guy from the Netherlands”]] ([[User talk:Netherin5|talk]]) {{CURRENTTIME}}, {{CURRENTDAY}} {{CURRENTMONTHNAME}} {{CURRENTYEAR}} (UTC)
:Hi! {{User:PoolloverNathan/Signature}} {{CURRENTTIME}}, {{CURRENTDAY}} {{CURRENTMONTHNAME}} {{CURRENTYEAR}} (UTC)
:hi! [[User:JLZ0kTC5|JLZ0kTC5]] ([[User talk:JLZ0kTC5|talk]]) {{CURRENTTIME}}, {{CURRENTDAY}} {{CURRENTMONTHNAME}} {{CURRENTYEAR}} (UTC)
:Hi! [[Special:Contributions/172.69.68.22|172.69.68.22]] {{CURRENTTIME}}, {{CURRENTDAY}} {{CURRENTMONTHNAME}} {{CURRENTYEAR}} (UTC)Bumpf
:Hi again? Random is [[Special:Random|weird]]. {{User:PoolloverNathan/Signature}} 14:24, 14 November 2022 (UTC)
:Yea, random brought me back here too lol. {{User:EnderPlays}} 01:43, 17 November 2022 (UTC)
:Hi! [[Special:Contributions/162.158.2.46|162.158.2.46]] 20:42, 6 December 2022 (UTC)
Hi [[Special:Contributions/172.70.230.159|172.70.230.159]] {{CURRENTTIME}}, {{CURRENTDAY}} {{CURRENTMONTHNAME}} {{CURRENTYEAR}} (UTC)
Hi!
:Hi, random is fun. --RandomInternetViewer {{CURRENTTIME}}, {{CURRENTDAY}} {{CURRENTMONTHNAME}} {{CURRENTYEAR}} (UTC)
:Hi. Got here from random :) {{CURRENTTIME}}, {{CURRENTDAY}} {{CURRENTMONTHNAME}} {{CURRENTYEAR}} (UTC) -[[User:Theunlucky|Theunlucky]] ([[User talk:Theunlucky|talk]]) 21:04, 15 December 2022 (UTC)
:At this point, I feel like random is slightly biased. Aside: why does everyone's signature end in <code><nowiki>{{CURRENTTIME}}, {{CURRENTDAY}} {{CURRENTMONTHNAME}} {{CURRENTYEAR}}</nowiki></code>? {{User:PoolloverNathan/Signature}} 16:24, 3 May 2023 (UTC) (in case the same thing happens to me: 16:24, 3 May 2023)
Hi people [[Special:Contributions/162.158.146.209|162.158.146.209]] {{CURRENTTIME}}, {{CURRENTDAY}} {{CURRENTMONTHNAME}} {{CURRENTYEAR}} (UTC)

Hello from very slightly in the future! [[Special:Contributions/172.70.162.56|172.70.162.56]] {{#time:H:i, d F Y (e)|+1 minute}}
:That comment was so last year. {{User:PoolloverNathan/Signature}} {{#time:H:i, d F Y (e)|+1 year}}

Hi! [[User:WhatDoWeDoNow|WhatDoWeDoNow]] (visited Jan 17th, 2023)

:Hi!
Hello, future (and past) sandbox visitors! I got here from random too. :) [[User:LostXOR|LostXOR]] 2023-03-28
:I am here from the future. I come from March 31st, in the year of 2023 to say hello. [[User:WhatDoWeDoNow|WhatDoWeDoNow]] ([[User talk:WhatDoWeDoNow|talk]]) 03:13, 1 April 2023 (UTC)
'''Hello'''. This page is originally used for testing out the Main Page features. Don't spam! [[User:ClassicalGames|ClassicalGames]] ([[User talk:ClassicalGames|talk]]) 03:41, 14 April 2023 (UTC)

hello world! (random page sent me here) [[User:Sci09273.15|Sci09273.15]] ([[User talk:Sci09273.15|talk]]) 17:26, 14 April 2023 (UTC)

Hello. Got here the same way as everyone else (Random page). [[Special:Contributions/172.71.214.128]] {{CURRENTYEAR}}-{{CURRENTMONTH}}-{{CURRENTDAY}} {{CURRENTTIME}} (UTC)

Greetings! (I wanted to be different (And I also got here via Random Page)) [[User:Trogdor147|Trogdor147]] ([[User talk:Trogdor147|talk]]) 18:34, 11 May 2023 (UTC)

Shalom! (randint too)
[[User:GetPunnedOn|GetPunnedOn]]
8:33 14/5/2023

Hello from Canada!

:Hi!!.! [[User:Trogdor146|“Person whose both more and less related to Trogdor147 than you would think”]] {{CURRENTTIME}}, {{CURRENTDAY}} {{CURRENTMONTHNAME}} {{CURRENTYEAR}} (UTC)
::"who is"/"who's", not "whose"... (I'm only here because of the above edit, that I wished to comment about the .sig for, but Hi from me too anyway.) [[Special:Contributions/162.158.74.47|162.158.74.47]] 20:00, 24 June 2023 (UTC)

2789: Making Plans

2023-07-03T20:06:29Z

XKCD Official:

{{comic
| number = 2789
| date = June 14, 2020
| title = Making Plans
| image = making_plans_2x.png
| imagesize = 217x396px
| noexpand = true
| titletext = Oh no, I haven't checked in with Yvonne in YEARS.
}}

==Explanation==
This comic is about bias due to {{w|alphabetical order}}. According to Wikipedia, "The practice in certain fields of ordering citations in bibliographies by the surnames of their authors has been found to create bias in favor of authors with surnames which appear earlier in the alphabet, while this effect does not appear in fields in which bibliographies are ordered chronologically."[https://decisionslab.unl.edu/pubs/stevens_duque_2018_SM.pdf] Similar effects have also been identified with the ordering of candidates on ballot papers.[https://electionlab.mit.edu/research/ballot-order-effects] In essence, humans tend to favor whatever is at the top of any given list or data set, or may only assess the first few options until they reach one that is 'good enough', thus never evaluating those further down the list; this is one reason why random shuffling is important in any scientifically rigorous trial or opinion survey.

In the comic, [[Cueball]] is telling [[Megan]] about some of his upcoming plans; tonight he had arranged a meet-up with contacts whose names start with A or B, tomorrow's socializing involves a larger group of A-contacts, but there seems some doubt over some of them.

By this point, though, there is a clear pattern: Cueball has been contacting friends based upon their alphabetical priority in his list of names, instead of making more practical social decisions. One alternative is to maintain contact with those who (regardless of name) were already in more recent and ready contact, perhaps by rearranging the list by "most recently talked to". Although, arguably, this could also be socially detrimental; anyone who happened to descend out of recent contact might never be contacted ''ever again''. Again, these social pitfalls are something that almost everyone has to try to deal with, but Cueball's 'logical' way of handling it is ironically one of the more socially illogical methods available.

The title text continues the joke, implying that Cueball rarely makes it to the bottom of his alphabetical list; as such, he has not reached out to his friend Yvonne in a very long time. She may even have assumed he has been {{w|Ghosting (behavior)|ghosting}} her, having seemingly not attempted to make return contact for that while either, but Cueball seems unable to distinguish between willing and enthusiastic contacts in general so his general social ineptness may be as much to blame as the enforced alphabetical priority of his friendship groups.

==Transcript==
:[Cueball is talking to Megan.]
:Cueball: Tonight is pub trivia with Annie and Beth.
:Cueball: And tomorrow Alex and I are seeing a movie. I also invited Andrew and Amy but I haven't heard back.

:[Caption below the panel:]
:I'm realizing I should really switch to sorting my phone contacts by most recent.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Phones]]
[[Category:Social interactions]]

270: Merlin

2023-07-03T20:06:02Z

XKCD Official:

{{comic
| number = 270
| date = May 30, 2008
| title = Merlin
| image = merlin.png
| titletext = I mean, the black-and-white stuff was running backward, but it hardly mattered to the story.
}}

==Explanation==
{{w|Merlin}} is a wizard who features prominently in various retelling of the legend of King Arthur. ''{{w|The Once and Future King}}'' by author {{w|T. H. White}} is one of the most popular versions of the legend, and in it, Merlin is described as living backwards through time, as [[Cueball]] and [[Megan]] discuss in this comic (this is also briefly mentioned in the musical ''{{w|Camelot (musical)|Camelot}}'', which is based on this version of the story).

In the comic, Cueball is speculating philosophically on how this would have affected Merlin's life as he started life with all his memories, and gradually lost them, comparing this to Megan's own sense of unreality at goodbyes.

Many old people do, however, end up alone without friends or family. And they may do nothing but watch TV all day. They might also lose their memory. So in this respect, Merlin's last days may not be so different from many real people's, except of course that Merlin was supposed to live in the late 5th and early 6th centuries with no access to DVDs or even TV.

''{{w|Memento (film)|Memento}}'' is a movie telling the main parts of its story backwards, while a few black-and-white scenes are straightforward. So when Merlin watches the movie, he sees nearly the whole story in its actual order, and the title text drives home the joke by noting that these few scenes, which make more sense to someone with normal perceptions than the rest of the movie, would make less sense to him.

Normal old people would not be able to enjoy ''Memento'' like Merlin. Although he would of course always have remembered seeing it when he got old, until the day he saw it and then forgot it afterwards...

==Transcript==
:[Cueball and Megan standing by a train on a platform.]
:Megan: I'm bad at goodbyes. At some level I never think they're for real.
:Cueball: They make me think of T. H. White's Merlin.

:[They are still standing at the edge of the platform, but the train is no longer in the frame.]
:Megan: Oh?
:Cueball: He lived backwards, remembering the future and not the past. To him, final goodbyes meant nothing, while first hellos were tearful and bittersweet.

:[Zooming out, the rail closest to the platform becomes visible.]
:Megan: Huh - so over the years he'd forget all his friends.
:Megan: Must've been lonely.
:Cueball: Yeah. He ended up just sitting around at home watching DVDs all day. The best was the time he rented 'Memento'...

:[Merlin with pointy hat and long white beard is sitting in a couch with the remote, watching TV which emits light and is clearly hooked up to a device (a DVD player).]
:Merlin: Well, that was straightforward.

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

2558: Rapid Test Results

2023-07-03T20:05:45Z

XKCD Official:

{{comic
| number = 2558
| date = December 22, 2020
| title = Rapid Test Results
| image = rapid_test_results.png
| titletext = A solid red area with two white lines means that you have been infected with the anti-coronavirus, COVID+19, which will cure anyone you have close contact with.
}}

==Explanation==
This comic is another in a [[:Category:COVID-19|series of comics]] related to the {{w|COVID-19 pandemic}}.

This comic is a joke about COVID-19 rapid {{w|lateral flow test}} results. These devices are used in many countries for individuals to test their own nasal and oropharynx fluid for evidence of COVID-19 virus to detect asymptomatic infection. These tests have two indicator strips - a test line for covid-19 and a control line to check the device is working correctly. Where a control line is not present, the test should be ignored and repeated. Until comparatively recently {{w|Pregnancy test|pregnancy}} was the occasion [[583|most familiar]] for requiring this form of test.

The first 2 answers are the standard indicators for a negative and positive result, but Randall takes this to absurdity, see below in the [[#Table of results|table]].

The title text interprets the hyphen in "Covid-19" as a negative sign to make a mathematical joke. Here Randall postulates a counterpart virus to Covid-19, resulting in a test with inverted colors, which he names Covid+19. When combined this anti-coronavirus exactly matches the original one and results in zero Covid, curing those who had previously been infected.

This was the last comic before this year's [[:Category:Christmas|Christmas comic]]. It was about Covid-19 testing. The last comic before the 2020 Christmas comic, [[2402: Into My Veins]], was about the Covid-19 vaccine.

===Table of results===
{| class="wikitable"
!Result
!Interpretation
!Explanation
|-
|Control line only
|Negative
|As for all such actual tests, the Control line indicates that the test has run without error. Without this Control line (which ''always'' shows on a correctly functioning test after proper use), a lack of result on the test strip is meaningless.
A control line with no Test line indicates that the molecule being tested for is not present.

|-
|Control and test line
|Positive
|This clearly shows the (un)desired test result, with both the Control line and the indicator of the tested-for condition.
|-
|2 wavy lines resembling the {{w|Approximation#Typography|approximately equal}} sign
|Approximately positive
|While it would be possible to make the test produce wavy line(s) by default, and some versions 'activate' more complex patterns such as tick-marks or wording, these are still binary yes/no results. The waviness or other patternation would not normally be contingent upon the testing state it must reveal, and the complicated pattern could result in a fainter Test line (However, {{w|National Health Service|NHS}} advice states that any positive line, no matter the strength, should be considered a positive).

A real test intended to produce straight lines might become wavy if manufactured poorly. Two lines would still indicate a positive test, but the poor quality of the device calls into question that result - making "approximately positive" an appropriate description.

Whilst this may have been unintended, it is worthwhile noting that lateral flow tests sacrifice some accuracy in order to be quick and cheap. They therefore have some risk of {{w|false-positive}} test results, hence the need for a follow-up gold-standard laboratory controlled confirmation test. In this sense, a positive rapid test result would give an approximately positive result.
|-
|2 lines closer together than usual
|Positive (college ruled)
|This is the same as the Positive result, just with less distance between the two lines. {{w|Ruled paper#United States|College ruled}} refers to how college ruled notebooks in the United States have narrower spacing between the lines.
Again, there is no simple way to make the test reveal different patterns as a result-indicator of any qualitative or quantitative result; this is not a different result from the original Positive. It also remains more desirable to maintain an easily-identifiable separation between lines and not risk the Test and Control lines bleeding together into one.
|-
|Five lines of decreasing lengths
|Good cell signal
|Mimics the standard image for a strong mobile (or cellular in the United States) phone signal.
This implies that the Rapid Test being used in the comic can also detect cellphone signals, which is both strange and useless for someone trying to test themselves for COVID-19 (but useful to know if you're planning to call a hospital). Furthermore, it is unknown how a chemical test can pick up on electromagnetic phenomena involving radio waves.
|-
|2 lines on a background of radiating lines
|Did you know these lines are actually parallel?
|This is a reference to an {{w|optical illusion}} called the {{w|Hering illusion}}, where two parallel lines appear to bend outward.
Whether the radial lines can (or should) be designed into the test has no bearing upon the core test, and probably won't cause misidentification of whether the test reveals one or two clear "straight" lines.
|-
|Multiple lines in the shape of a scary stick figure
|The Blair Witch is near
|In the found-footage movie ''{{w|The Blair Witch Project}}'', stick figures shaped like this indicated that the Blair Witch was near.
The type of rapid test used for COVID-19 probably does not have any useful method for revealing the proximity of witchcraft,{{fact}} unless a witchcraft-related molecule could be identified that can be indicated within the sample material itself.
|-
|Three lines
|Click to expand COVID menu
|A reference to {{w|Hamburger button|hamburger buttons}}, an icon that is widely used on websites to reveal a menu. It is especially used on mobile versions of sites designed to be read on a small screen, where compressing a menu until needed saves space.
This seems to show that the test can provide more data via a hidden menu, which shouldn't be able to fit on a small screen such as the one shown in the comic. Many COVID-19 tests have associated apps alongside the rapid test device for better analysis and dissemination of the results, but such an app isn't normally integrated into the rapid test device itself.
|}

==Transcript==
:[Header above the comic:]
:Interpreting Rapid Test Results

:[What follows is a set of 8 possible rapid test results for COVID-19.]

:[One line on the "C".]
:Negative

:[Two lines, one on the "C" and one on the "T".]
:Positive

:[Two curvy lines on the "C" and the "T", resembling the "approximately equal" sign.]
:Approximately positive

:[Two lines, not on the "C" or the "T", but they are instead closer together.]
:Positive (college ruled)

:[Five lines resembling a cell signal symbol.]
:Good cell signal

:[Two straight lines, on the "C" and "T", with lines going outward from the centre, giving an illusion of the lines being curved.]
:Did you know these lines are actually parallel?

:[One line on the "C", and two lines in a cross with one line sticking upward of the center of the cross.]
:The Blair Witch is near

:[Three lines, with one on the "C", one on the "T", and one in the middle of the "C" and "T".]
:Click to expand Covid menu

{{comic discussion}}
[[Category: COVID-19]]
[[Category: Comics with color]]
[[Category: Charts]]
[[Category: Fiction]]