explain xkcd - User contributions [en]

Talk:1780: Appliance Repair

2023-11-05T01:36:04Z

Sollyucko: this reminds me of Young Sheldon and Modern Family episodes

He took it apart because it's not working. It's not working because he took it apart. And so we are all a part of the Great Circle of Life. [[Special:Contributions/162.158.122.102|162.158.122.102]] 15:22, 2 January 2017 (UTC)

Reminds me of my Christmas present to my parents - a [https://www.amazon.com/Double-Socket-Electric-Sockets-Outlets/dp/B00S5ZJTY0 USB mains socket], and my time and work to install it. The old non-USB socket was working fine, but when I removed it, I couldn't get the new one installed due to some unusual wiring, and couldn't replace the old one either. This also cut the power to the fridge! We had to call an electrician to fix the problem - literally, that it wasn't working because somebody took it apart... [[User:Cosmogoblin|Cosmogoblin]] ([[User talk:Cosmogoblin|talk]]) 15:57, 2 January 2017 (UTC)

I added onto the transcript and description so it would be less barebones. If not, please add onto my work. Thanks. (It feels good to be back after so long. :)) --[[User:JayRulesXKCD|JayRulesXKCD]] ([[User talk:JayRulesXKCD|talk]]) 16:56, 2 January 2017 (UTC)
:Randall was right. :)) does look mismatched and wrong. How do you fix it?! --[[User:JayRulesXKCD|JayRulesXKCD]] ([[User talk:JayRulesXKCD|talk]]) 16:56, 2 January 2017 (UTC)
::I'm a fan of putting a space after the smiley (like this :) ) it can still make it look unbalanced, but in my opinion it is better than the double paren.[[Special:Contributions/108.162.238.11|108.162.238.11]] 12:24, 4 January 2017 (UTC)
:::Or, there's always unicode. 😀 --[[User:JayRulesXKCD|JayRulesXKCD]] ([[User talk:JayRulesXKCD|talk]]) 15:38, 4 January 2017 (UTC)

120V is a US standard - in the civilized world, or at least Europe, single phase domestic supply is 230V.

The three phases are 120 degrees apart. Wikipedia is over there.
[[Special:Contributions/141.101.99.137|141.101.99.137]] 18:10, 2 January 2017 (UTC)

I removed all references to actual voltage values. I was thinking only for me... Canada also uses 120V (and 240V too, for house heating, clothes dryers, and ovens), along with another few countries.--[[User:Jeanrenaud|Jeanrenaud]] ([[User talk:Jeanrenaud|talk]]) 19:06, 2 January 2017 (UTC)

Not sure where you get the idea that Cueball is running an appliance repair business. Seems simpler to assume that he is taking apart his own humidifier. [[User:Rtanenbaum|Rtanenbaum]] ([[User talk:Rtanenbaum|talk]]) 20:27, 2 January 2017 (UTC)

:The Tautology Club might be involved :-)
:--[[User:Lou Crazy|Lou Crazy]] ([[User talk:Lou Crazy|talk]]) 11:06, 3 January 2017 (UTC)

;Title Text

Maybe Randall is simply giving the game away here: If it is a three-phase motor, then it should not be referred to as the humidifier. And if it is being referred to as the humidifier, then it likely is leaking, or smoking, the smoke of which is confused for the production of mist. On top of the three-phase v.s. one-phase, I think we have a good game going. {{unsigned ip|108.162.222.16}}

There doesn't seem to be any direct indication of a repair service being run by Cueball. Also, the fact that he is holing a 3-phase motor doesn't mean the three phase motor is the problem. The comic directly states that the motor being removed, not the motor itself, is the problem. (not to mention that a three-phase motor by itself is not necessarily suspicious; instead of the type of mains-connected 3-phase motor described above, it could be a small brushless motor, many of which are 3-phase, and while more expensive can be expected in small electronics under digital control)[[Special:Contributions/162.158.75.130|162.158.75.130]] 10:14, 4 January 2017 (UTC)

;The part is not necessarily broken

Cueball never says that the motor is broken (as most appliance repair people would do when they find the problem). He merely states that the part came from a broken machine--something that was already known. Updated description to include this subtlety. [[Special:Contributions/172.68.34.94|172.68.34.94]] 19:50, 21 September 2017 (UTC)

This reminds me of a couple of TV episodes:
*Young Sheldon, S2E1 (2018-SEP-24) "A High-Pitched Buzz and Training Wheels": Sheldon disassembles the family's fridge in an attempt to fix it, but is unable to put it back together himself
*Modern Family, S8E13 (2017-FEB-15) "Do It Yourself": despite it seeming like it's going to go badly, Phil successfully manages to replace the moisture sensor in the family's clothes-dryer
[[User:Sollyucko|Sollyucko]] ([[User talk:Sollyucko|talk]]) 01:36, 5 November 2023 (UTC)

Talk:1717: Pyramid Honey

2023-10-25T21:50:14Z

Sollyucko: website moved to https://irna.fr/Honey-in-the-pyramids.html

Seems like this could be the [http://www.smithsonianmag.com/science-nature/the-science-behind-honeys-eternal-shelf-life-1218690/ Smithsonian reference]! --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 13:53, 8 August 2016 (UTC)

Anyone know what the counter source or argument is?{{unsigned ip|141.101.98.16}}

This looks like it could be the source that inspired the strip:

http://irna.lautre.net/Honey-in-the-pyramids.html{{unsigned ip|173.245.54.53}}
:According to Internet Archive's Wayback Machine, the website moved to https://irna.fr/Honey-in-the-pyramids.html [[User:Sollyucko|Sollyucko]] ([[User talk:Sollyucko|talk]]) 21:50, 25 October 2023 (UTC)

Looks like a place to start digging for references: http://bumblehive.com/honey-was-not-found-in-pharaohs-tombs/ {{unsigned|JourneymanWizard}}

Did Randall draw the wrong colored hat?? [[User:Jameslucas|jameslucas]] ([[User talk:Jameslucas|" "]] / [[Special:Contributions/Jameslucas|+]]) 15:09, 8 August 2016 (UTC)
: Nah, I think it's just IRL trolling. [[Special:Contributions/173.245.54.80|173.245.54.80]] 15:34, 8 August 2016 (UTC)

Could this be the ned of Black Hat? The end of ''xkcd?!'' [[Special:Contributions/173.245.54.51|173.245.54.51]] 16:06, 8 August 2016 (UTC)

Correction: this doesn't put "Megan unwillingly into the same camp as conspiracy theorists" it puts Black Hat there.{{unsigned ip|108.162.246.111}}
: No. Black hat is very much willing to join the conspiracy theorist camp. Rather, he creates it. Megan isn't a conspiracy theorist, her scepticism towards Cueballs honey claims are perfectly valid. But to an outside observer, she promotes the same viewpoint as Black hat. Indeed, Black hat even refers to Megan for "evidence". So Megan is forever assosiated with the Pyramid Honey truthers, despite having nothing to do with them. --[[Special:Contributions/141.101.80.70|141.101.80.70]] 09:35, 9 August 2016 (UTC)

[https://www.reddit.com/r/xkcd/comments/4wq6pf/xkcd_1717_pyramid_honey/d690yct This Reddit thread] cites https://en.wikipedia.org/wiki/Honey#Preservation and https://en.wikipedia.org/wiki/Honey#Ancient_times [[Special:Contributions/172.68.35.71|172.68.35.71]] 18:58, 8 August 2016 (UTC)

The phrase "a weird hill to die on" could probably use an explanation, too, as I'd never heard of that (or its apparent source phrase "Is this the hill you want to die on?", based on some quick googling) before. [[Special:Contributions/199.27.133.101|199.27.133.101]] 23:04, 8 August 2016 (UTC)
: "Is this the hill you want to die on?" sounds to me like a line from a war movie, e.g. this one https://en.wikipedia.org/wiki/Hamburger_Hill. Maybe its origin is indeed something military, as some sources suggest: http://english.stackexchange.com/questions/162813/what-is-the-origin-of-the-phrase-a-mountain-im-willing-to-die-on [[User:Elektrizikekswerk|Elektrizikekswerk]] ([[User talk:Elektrizikekswerk|talk]]) 06:49, 9 August 2016 (UTC)

I have a possible source for the "weird hill to die on" reference, saw it on BBC a while back: Body on the Moor; http://www.bbc.com/news/resources/idt-e8c6cbab-da44-4a3c-8f9b-c4fccd53dd24. {{unsigned ip|108.162.244.85}}

Every particle physicist knows that the shelf life of honey is at most 1042 years, just like everything else. --[[Special:Contributions/108.162.215.129|108.162.215.129]] 00:51, 9 August 2016 (UTC)
: Only if you assume nucleon decay. If Earth doesn't get absorbed into a black hole and then Hawking Radiated out, the honey would just continue to cool long into the heat death of the universe, eventually cold-fusioning via quantum-tunnelling into Iron-56 by 101500 years https://en.wikipedia.org/wiki/Future_of_an_expanding_universe#Future_without_proton_decay. [[User:Ehryk|Ehryk]] ([[User talk:Ehryk|talk]]) 02:23, 10 August 2016 (UTC)

re: tooltip - I thought it was a floating giant eye? --[[Special:Contributions/173.245.54.28|173.245.54.28]] 00:59, 9 August 2016 (UTC)

The "weird hill to die on" phrase could mean a point of view Black Hat will defend to the last, regardless the sense of it (which makes sense with the militarian source).
He might find such a thing worth to find because it would give his entire life a (though in general maybe and in this case definitely unuseful) purpose.
furthermore, by simply spreading Megan's claim without considering the nuances of her point and questioning it thouroughly he does basically the same as ll the people who claim honey's shelf life to be infinite (who apparently never thought of asking for further information where exactly the honey was found and by whom).
{{unsigned ip|162.158.83.228}}
:when the explanation for "weird hill to die on" as a phrase gets settled the explanation should probably also reference Black Hat's mixing of the metaphorical use (a debate position or principled stand) and a literal hill ("[A]ll the real ones are too far from my house.") [[Special:Contributions/108.162.237.242|108.162.237.242]] 12:24, 9 August 2016 (UTC)

So, the "hill to die on" expression does relate back to the military some. Hills are good defensive places (ask any Civilization player). It's much easier to defend yourself when the other army is trying to run up a hill. Hence why lots of forts and military battles are associated with hills. The hill you die on, then, is that area of contention that you'll stubbornly defend to the very end. And of course Black Hat is making something like a zeugma when he mixes the metaphorical and literal meanings. {{unsigned ip|108.162.216.152}}

"a hill to die on" appears in chapter 27 of the novel "For Whom the Bell Tolls", by Ernest Hemingway, published in 1940, about the 1936-1939 Spanish Civil War in which many non-Spanish volunteers joined the fight on one side or the other for ideological reasons. The book ends with the American protagonist, alone and wounded, preparing to ambush the enemy to buy time for the escape of his comrades; he will probably not survive. [[User:GrayJay|GrayJay]] ([[User talk:GrayJay|talk]]) 04:36, 10 August 2016 (UTC)--

Some facts about honey [http://www.youtube.com/watch?v=7FlzHiURdTs Honey: Bacteria's Worst Enemy] --[[Special:Contributions/162.158.92.207|162.158.92.207]] 14:27, 9 August 2016 (UTC)

"While some conspiracy theories turn out to be true, most, like the two mentioned here, are fake": while it's completely clear that the Moon landing not happening theory is false, we can't be 100% sure about the 9/11 theories at the moment (of course, the one mentioned is highly unlikely, but it's not refuted to the level of the moon landing conspiracy theories at the moment). I suggest correcting this statement into something weaker.{{unsigned ip|198.41.242.75}}

Wouldn't Black Hat just be trolling everyone else? I can't find the idea among the discussion, and neither in the the explanation, while it seems the obvious one to me. Deliberately spreading conspiracy theorists seems exactly his thing (just like the way he met Danish was a form of deliberate trolling...) [[Special:Contributions/141.101.105.10|141.101.105.10]] 15:25, 10 August 2016 (UTC)
:I totally agree. I'm now a "Black Hat always behaves like Black Hat truther"... :-) No seriously I agree and have added this as an alternative reason for his behavior. Maybe my version could be improved though? --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 11:51, 15 August 2016 (UTC)

I've tried to keep honey in my fridge for a while. After five years or so, it's mostly just so much crystallized sugar. In principle, after a sufficiently long time (probably less than a millenium), all the sugar should probably crystallize away, leaving something that isn't really honey. [[Special:Contributions/172.68.10.51|172.68.10.51]] 01:20, 12 August 2016 (UTC)

"Megan seems to think it is OK as long as it is her opinion Black Hat spreads out." You get this from the phrase "Oh well"? A common statement of resignation? [[Special:Contributions/108.162.210.196|108.162.210.196]] 01:33, 12 August 2016 (UTC)
:Has been changed by someone now, that's what so nice about a wiki ;-) --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 11:51, 15 August 2016 (UTC)
::Yeah, just look at all that consensus established in the discussion field. [[Special:Contributions/108.162.210.196|108.162.210.196]] 23:46, 18 August 2016 (UTC)

Perhaps an alternate explanation for Black Hat's quote "and all the real ones are too far away from my house" would be that he's referring to the real problems. The phrase, "a hill to die on" refers to something you'll defend to the bitter end-- there are many things in the world that need to be fought for, many injustices against which we ought to direct our energy to stopping... and yet people find time to waste fighting about irrelevant, stupid things (like whether or not honey has infinite shelf-life-- I mean, really, how many lives is this going to change?). The reason for this is because to fight for those things, the important things, requires one to actually ''do'' something, to get off his/her butt and put effort, energy, money, and more into solving it. But whining/ranting on twitter about something that doesn't matter (or can't be solved by whining/ranting on the internet)? While it takes a lot of [wasted] time and energy to do that, its significantly less effort than, well, doing something meaningful to make a positive difference in the world. So that's why I think Black Hat meant: not that the weird hills were literally too far from his house, but that all the important things to fight for would take too much effort (he would have to get off his butt and go somewhere and strive). Or I might be reading too much into this due to my personal annoyance with pointless internet crusades. *shrug* ~EinarAmund {{unsigned ip|108.162.215.191}}

Black Hat, being Black Hat, is going to troll the internet by stating honey can not last that long (just as Megan said). His scam assume the opposers will bombard him with honey jars to prove their point, with an amount allowing him to literally build a hill made of honey jars. [[Special:Contributions/141.101.98.15|141.101.98.15]] 10:41, 18 August 2016 (UTC)

The FDA classifies honey as raw meat, if my good friend Gabee is telling the truth.

2193: Well-Ordering Principle

2023-06-12T05:54:11Z

Sollyucko: mention the axiom of choice

{{comic
| number = 2193
| date = August 23, 2019
| title = Well-Ordering Principle
| image = well_ordering_principle.png
| titletext = We could organize a nationwide old-photo-album search, but the real Worst McFly is probably lost to time.
}}

==Explanation==
In the comic, [[Megan]] has found a genie lamp. A genie (or {{w|Jinn}}) in a lamp is a supernatural, immortal being from many fairy tales, the most well known that from {{w|Aladdin}}, who grants one or more wishes to the person who frees it, such as by polishing or opening the lamp. Instead of wishing for multiple wishes, flight, money, or other "traditional" wishes, Megan instead wishes to see the worst Marty McFly Halloween costume.

{{w|Marty McFly}}, played by actor {{w|Michael J. Fox}}, is a main character of the science fiction film about time travel ''{{w|Back to the Future (franchise)|Back to the Future}}'', which was released, [[:Category:Comics to make one feel old|we are reminded]], over thirty years ago, starting a series of sequels. The films are popular, so many people dress up as McFly or Doc Brown, the other main character, on {{w|Halloween}}, a holiday on October 31 when it is traditional in the USA to wear {{w|Halloween costume|different costumes}}. McFly's outfit in the original film consists of little more than an orange vest, jean jacket, checkered shirt, jeans, and sneakers. It would seem difficult to get this wrong.

In the final panel, the genie questions why she would wish for something so mundane, when he has the power to grant wishes beyond her wildest dreams. Megan, being savvy of tropes, used in fiction since biblical times, points out that encounters with wish-granting entities often turn out to be traps. Genies in fiction will often interpret wishes in ways the wisher did not intend, and particularly mean-spirited ones will {{tvtropes|JackassGenie|twist a mortal's desire into their own personal hell}}. Even when the wish-granting entity isn't malicious, they're often portrayed as carrying unintended consequences, such that extremely consequential wishes become extremely dangerous. So Megan tries to play it safe by wishing for something innocuous and with little room for harmful side-effects. Unfortunately, Megan appears to have forgotten the overarching trope: all wishes can be twisted against the wisher.

The genie may also be reluctant to fulfill the wish due to the insurmountable practical difficulties of fulfilling such subjective, ill-defined request. The {{w|well-ordering principle}} is a mathematical fact stating that every non-empty set of positive integers contains a least element; a generalization of this is the {{w|well-ordering theorem}} which is equivalent (given {{w|Zermelo–Fraenkel set theory}}) to the {{w|axiom of choice}}, the subject of [[982: Set Theory]]. This principle would apply to Megan's request if there was guaranteed to be an absolute worst costume of Marty McFly. However, subjective {{w|preference}}, while {{w|Reflexive relation|reflexive}} and {{w|Transitive relation|transitive}}, is not {{w|Well-founded relation|well-founded}} (or {{w|Symmetric relation|symmetric}} or necessarily {{w|Antisymmetric relation|antisymmetric}} or {{w|Connex relation|(semi-)connex}} for that matter) and is therefore considered to be a {{w|preorder}}, also called a quasiorder. This means that the genie may not be able to fulfill Megan's wish if the selection is based on the preferences of any one person. For example, the genie may have no opinion on the quality of any McFly costume, or might judge them on criteria completely different from Megan's. Her own criteria might apply to some pairs of costumes but not others, leading to ambiguity as to which is the worst, and no way to say whether any of the candidate possibilities are as bad as the others.

While Megan isn't explicitly wishing for a {{w|Public opinion|common or widely-shared opinion}}, the title text contemplates organizing a "nationwide" search. People's preferences can be combined, such as with a {{w|mean opinion score}} which, while not strictly well-ordered, is usually able to identify a single worst costume, or at least a set of costumes tied for worst place according to aggregate subjective preferences. There are [https://www.docdroid.net/bcKvZmM/preference-aggregation.pdf many other ways to combine preferences] (e.g. voting) but none of them meet all of the criteria considered desirable, as demonstrated by {{w|Arrow's impossibility theorem}}. There is no way to exclude the possibility that even an omniscient and omnipotent genie might be {{w|Omnipotence paradox|technically unable}} to fulfill the wish, at least without, for example, changing one or more persons' preferences or modifying the space-time continuum to retroactively change the quality of some costumes of the past. The genie could fulfill the wish by showing Megan every McFly costume ever worn, which would necessarily show her the worst by any possible definition, but could be the trap she was hoping to avoid because viewing all the "hundreds of thousands" would take an inordinately long time.

The title text may explain why Megan is interested in this wish: any means available to her would be restricted to a geographic area's (nationwide) photographs or drawings from memory. It is likely the worst costume was either never photographed, or isn't remembered accurately by those who saw it (it is "lost to time" -- which usually is just a figure of speech, but may actually be ''literally'' true in this case given the ''Back to the Future'' series' central theme of time travel). By asking the genie to show her, she might be able to see the truly worst costume without being restricted to only those for which evidence remains. Such a wish fulfillment might even require actual time travel to the time and location where the costume existed. The title text can also be interpreted as [[Randall|Randall's]] wish to know about the worst costume. So this is not Megan but Randall who has the wish to see this costume. The best we can do today is to look through all the available photos of McFly costumes. But even if one of those could be agreed upon to be the worst, there is no guarantee that there is not even worse versions that is not documented for posterity. In this interpretation, what Randall really would like is to use a dangerous genie wish to get around these difficulties.

An additional, subtle pun plays on the word "well". In European folklore, {{w|Wishing_well|water wells}} are often associated with spirits which may grant wishes, similar to genies. Thus, Megan's explanation of why she made a simple request of the genie is a statement of her "well-ordering principle"; her principle for ordering wishes from wells. (See also the [[:Category:Well|Well series]]).

==Transcript==
:[Megan rubs a lamp held in her hands. A genie appears from the end of the lamp. The genie resembles the top half of Cueball's body, with a head, torso, and crossed arms, but with a squiggle representing a puff of smoke in place of his legs.]
:Genie: Greetings, mortal. You have freed me. I will grant you one wish.
:Megan: Hmm.

:[Megan holding the lamp to her side. The genie is off-panel.]
:Megan: It's been over 30 years since ''Back to the Future'' came out. Since then, probably hundreds of thousands of people have tried to dress as Marty McFly for Halloween.
:Genie: OK, and?

:[Megan, holding the lamp to her side, talking to the genie, who is floating in the air.]
:Megan: Of those people, one of them must have done the worst job.
:Megan: My wish is to see their costume.

:[Megan still holding the lamp and talking to the genie. The genie is exasperated, and has his hands raised.]
:Genie: Not a billion dollars? Flight? Infinite wishes?
:Megan: These wish things are always traps.
:Megan: Just show me the worst McFly and we'll call it even.

{{comic discussion}}

[[Category:Comics featuring Megan]]
[[Category:Comics to make one feel old]]
[[Category:Fiction]]
[[Category:Math]]
[[Category:Back to the Future]]
[[Category:Genie]]

410: Math Paper

2023-02-03T18:48:16Z

Sollyucko: /* Math */ mention perfect numbers

{{comic
| number = 410
| date = April 14, 2008
| title = Math Paper
| image = math_paper.png
| titletext = That's nothing. I once lost my genetics, rocketry, and stripping licenses in a single incident.
}}

==Explanation==
The math paper [[Cueball]] is in the process of describing in this comic turns out to be nothing but an elaborate setup for a joke about {{w|imaginary friend}}s by taking the concept of "{{w|friendly number}}s" into the complex (imaginary) plane, which comprises complex numbers that have both a real and an imaginary part (see details [[#Math|below]]).

Cueball is challenged on this setup by his superiors, specifically the Cueball-like guy sitting at the end of the table, who look straight through his first line-up for the joke, and ask him directly if this is just a build-up for this joke. Cueball tries at first to look like he has no idea what he's talking about, then lowers his head, in shame, and finally tries to state that ''it might not be'' such a setup. But it is too late now.

Such a pun is both so obvious and so terrible that Cueball's superiors deem that he should no longer have a {{w|Licence to kill (concept)|license to ''math''}}, and they thus revoke Cueball's "math license." Of course you do not need a math license{{Citation needed}}, but that is part of the comic's concept along the lines mentioned here below and further elaborated in the title text.

It is a [[:Category:Banned from conferences|recurring theme]] in earlier xkcd comics that Cueball (or [[Randall]]) ends up being banned from holding presentations at conferences after a presentation turns out to be just an elaborate pun.

The title text takes the joke a step further, with the added hilarity of making the audience question exactly how Cueball/Randall was able to work a {{w|striptease}} into a presentation about {{w|genetic engineering}} and {{w|astrophysical}} rocket study (or possibly genetics and rockets into a striptease), and then even manage to lose all three licenses in one go. This is what TV Tropes calls a "{{tvtropes|NoodleIncident|noodle incident}}."

The whole comic is basically Randall making the joke that Cueball never got around to, but packing it up so we think it is about something else. Randall has often made such feeble jokes, but by putting them into a context where someone listening may comment on how bad that joke is or have to explain the joke, it somehow becomes alright, and he can get away with these jokes anyway. (See for instance [[18: Snapple]]).

===Math===
An {{w|imaginary number}} is a number that can be written as a real number multiplied by the imaginary unit ''i'', which is defined by its property ''i2 = -1'' (an impossibility for regular, "{{w|real numbers}}," for which all squares are positive). The name "imaginary number" was coined in the 17th century as a derogatory term, since such numbers were regarded by some as fictitious or useless, but over time, many applications in science and engineering have been found.

An imaginary number ''bi'' can be added to a real number ''a'' to form a {{w|complex number}} of the form ''a + bi'' (the formula shown at the bottom of Cueball's slide ), where ''a'' and ''b'' are called, respectively, the real part and the imaginary part of the complex number. If ''a'' and ''b'' are both integers, the complex number is called a {{w|Gaussian integer}} (as Cueball mentions). The {{w|complex plane}} is an X-Y plot with ''a'' on the X axis and ''b'' on the Y axis. (Such a plane is shown at the bottom of Cueball's slide).

Joel Bradbury (once) had the below cited and wonderful explanation of {{w|friendly number}}s on his site:

:What are Friendly Numbers?
:We need first to define a divisor function over the integers, written σ(n) if you're so inclined. To get it first we get all the integers that divide into n. So for 3, it's 1 and 3. For 4, it's 1, 2, and 4, and for 5 it's only 1 and 5.

:Now sum them to get σ(n). So σ(3) = 1 + 3 = 4, or σ(4) = 1 + 2 + 4 = 7, and so on.

:For each of these n, there is something called a characteristic ratio. Now that's just the divisors function over the integer itself: σ(n)/n. (This is the formula shown at the top of Cueball's slide). So the characteristic ratio where n = 6 is σ(6)/6 = 12/6 = 2.

:Once you have the characteristic ratio for any integer n, any other integers that share the same characteristic are called friendly with each other. (This is what is written in the frame in Cueball's slide, spelling friendly numbers as ''friendly #s''). So to put it simply, a friendly number is any integer that shares its characteristic ratio with at least one other integer. The converse of that is called a solitary number, where it doesn't share its characteristic with anyone else.

:1, 2, 3, 4, and 5 are solitary. 6 is friendly with 28; σ(6)/6 = (1+2+3+6)/6 = 12/6 = 2 = 56/28 = (1+2+4+7+14+28)/28 = σ(28)/28; this is due to both of them being {{w|perfect numbers}}.

==Transcript==
:[Cueball, holding a pointing stick, is using it to point at an equation on a panel. He is looking to the right. There are several parts of the panel that can be read. At the top, there is a formula. Below is a frame with text. Below again to the left is an X-Y plot with small dots all over all four quadrants, probably indicating the complex numbers with ''b'' on the Y and ''a'' on the X axis. Finally, right of this is yet another formula.]
:Cueball: In my paper, I use an extension of the divisor function over the Gaussian integers to generalize the so-called "friendly numbers" into the complex plane.
:Panel:
::σ(n)/n = d(n)
::Friendly #s share d(n)
::For a + bi...

:[The audience to the right of Cueball consist of two Cueball-like guys (one in front and one in the back), and between them are Hairbun, with glasses, and Megan. They sit around a table; only Hairbun is on the near side. The Cueball-like guy sitting to the right is at the end of the table, the other two are on the far side. The Cueball at the end of the table is talking, the other three have turned to look at him:]
:Guy at the end of the table: Hold on. Is this paper simply a giant build-up to an "imaginary friends" pun?

:[Back to Cueball, who stands speechless.]

:[One more beat panel with Cueball, who now looks down.]

:[Zoom out to Cueball and the front end of the table with the Cueball-like guy who has not spoken yet and Hairbun who now looks at Cueball. Cueball looks up again and speaks. The guy at the end of the table speaks off panel.]
:Cueball: It might not be.
:Guy at the end of the table (off panel): I'm sorry, we're revoking your math license.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Hairbun]]
[[Category:Comics featuring Megan]]
[[Category:Multiple Cueballs]]
[[Category:Banned from conferences]]
[[Category:Number theory]]
[[Category:Puns]]

2638: Extended NFPA Hazard Diamond

2022-06-28T03:09:02Z

Sollyucko: link to information about the NFPA square

{{comic
| number = 2638
| date = June 27, 2022
| title = Extended NFPA Hazard Diamond
| image = extended_nfpa_hazard_diamond.png
| titletext = With most labs, the hushed horror stories are about something like dimethylmercury or prions, but occasionally you'll get a weird lab where it's about the soda machine or the drop ceiling.
}}

==Explanation==
{{incomplete|Created by a SUBSTANCE WORTH $500 IN STREET VALUE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
This comic depicts an extension of [[wikipedia:NFPA 704|NFPA 704]], bringing it from 2x2 to 3x3 by adding 5 variously useful and humorous squares.

{| class="wikitable"
|+ Squares and explanations
|-
! Square !! Color !! Comic text !! Explanation
|-
| Top || Red || Flammability -> 0 || [[http://www.ilpi.com/msds/ref/nfpa.html Real NFPA 704 square]]. Denotes flammability.
|-
| Top Left || Blue || Health Hazard -> 4 || Real NFPA 704 square. Denotes the danger that the substance poses to living beings in ways other than flammability and reactivity.
|-
| Top Right || Yellow || Instability/Reactivity -> 2 || Real NFPA 704 square. Denotes how easily the substance reacts with other substances.
|-
| Center || White || (Special Hazard) || Real NFPA 704 square. Contains a symbol with additional notes on the substance. After this point, all squares are made up by Randall.
|-
| Center Left || Green || Number of digits in the street value ($/gram) -> 2 || Describes the order of magnitude of the price of one gram of the substance when sold illegally and informally. Most common illicit drugs would score 2 in this square.
|-
| Center Right || Dark Purple || How much of a hassle it is to dispose of -> 4 || Describes in a subjective (or maybe objective?) way how difficult the substance is to dispose of. While many things can be thrown in the trash with no additional procedures{{Citation Needed}}, biohazards that may carry diseases are often disposed of in special containers, and nuclear materials are notoriously difficult to safely dispose of. This square would be useful in limited contexts.
|-
| Bottom Left || Lilac || Number of federal agencies who want to know if you have any -> 3 || In many countries, including Randall's home country, the USA, the government has agencies dedicated to controlling or limiting the use of regulated substances, due to their use as drugs or as chemical weapons. While any given substance would probably be of one agency's interest, something that is both an environmental hazard and a chemical weapon component could interest, for example, both the Chemical Safety Board and the FBI Counterterrorism Division. This could also allude to the CIA's experiments with LSD, which is illegal to possess as a US civilian.
|-
| Bottom Right || Orange || How many times you have to scrub your hands after touching it before they stop smelling weird -> 1 || While the real NFPA 704 chart describes properties ranging from unsafe to potentially deadly, this square describes a minor but very real inconvenience. Some things are harder to wash off your hands than others, and, given that most people don't often work with dangerous substances {{Citation Needed}}, this would be a more common, but less relevant, concern for many people.
|-
| Bottom || Black || Number of times it's caused one of those terrifying lab accidents that chemists tell scary stories about late at night -> 2 || The result of this square, although dependent on how much the substance is researched in labs, can show how scared someone should be in handling the substance in question, especially if the number is more than one. Though the description is vague, this number could show how easy it is to cause ''some'' kind of reaction of a terrifying magnitude with this substance.
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
Know your extended NFPA hazard diamond:

Flammability: 0 (top)

Health hazard: 4 (top-left)

Instability/reactivity: 2 (top-right)

Number of digits in the street value ($/gram): 2 (left)

(Special hazard) (center)

How much of a hassle it is to dispose of: 4 (right)

Number of federal agencies who want to know if you have any: 3 (bottom-left)

How many times you have to scrub your hands after touching it before they stop smelling weird: 1 (bottom-right)

Number of times it's caused one of those terrifying lab accidents that chemists tell scary stories about late at night: 2 (bottom)

{{comic discussion}}

2638: Extended NFPA Hazard Diamond

2022-06-28T03:05:27Z

Sollyucko: add values to table

{{comic
| number = 2638
| date = June 27, 2022
| title = Extended NFPA Hazard Diamond
| image = extended_nfpa_hazard_diamond.png
| titletext = With most labs, the hushed horror stories are about something like dimethylmercury or prions, but occasionally you'll get a weird lab where it's about the soda machine or the drop ceiling.
}}

==Explanation==
{{incomplete|Created by a SUBSTANCE WORTH $500 IN STREET VALUE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
This comic depicts an extension of [[wikipedia:NFPA 704|NFPA 704]], bringing it from 2x2 to 3x3 by adding 5 variously useful and humorous squares.

{| class="wikitable"
|+ Squares and explanations
|-
! Square !! Color !! Comic text !! Explanation
|-
| Top || Red || Flammability -> 0 || Real NFPA 704 square. Denotes flammability.
|-
| Top Left || Blue || Health Hazard -> 4 || Real NFPA 704 square. Denotes the danger that the substance poses to living beings in ways other than flammability and reactivity.
|-
| Top Right || Yellow || Instability/Reactivity -> 2 || Real NFPA 704 square. Denotes how easily the substance reacts with other substances.
|-
| Center || White || (Special Hazard) || Real NFPA 704 square. Contains a symbol with additional notes on the substance. After this point, all squares are made up by Randall.
|-
| Center Left || Green || Number of digits in the street value ($/gram) -> 2 || Describes the order of magnitude of the price of one gram of the substance when sold illegally and informally. Most common illicit drugs would score 2 in this square.
|-
| Center Right || Dark Purple || How much of a hassle it is to dispose of -> 4 || Describes in a subjective (or maybe objective?) way how difficult the substance is to dispose of. While many things can be thrown in the trash with no additional procedures{{Citation Needed}}, biohazards that may carry diseases are often disposed of in special containers, and nuclear materials are notoriously difficult to safely dispose of. This square would be useful in limited contexts.
|-
| Bottom Left || Lilac || Number of federal agencies who want to know if you have any -> 3 || In many countries, including Randall's home country, the USA, the government has agencies dedicated to controlling or limiting the use of regulated substances, due to their use as drugs or as chemical weapons. While any given substance would probably be of one agency's interest, something that is both an environmental hazard and a chemical weapon component could interest, for example, both the Chemical Safety Board and the FBI Counterterrorism Division. This could also allude to the CIA's experiments with LSD, which is illegal to possess as a US civilian.
|-
| Bottom Right || Orange || How many times you have to scrub your hands after touching it before they stop smelling weird -> 1 || While the real NFPA 704 chart describes properties ranging from unsafe to potentially deadly, this square describes a minor but very real inconvenience. Some things are harder to wash off your hands than others, and, given that most people don't often work with dangerous substances {{Citation Needed}}, this would be a more common, but less relevant, concern for many people.
|-
| Bottom || Black || Number of times it's caused one of those terrifying lab accidents that chemists tell scary stories about late at night -> 2 || The result of this square, although dependent on how much the substance is researched in labs, can show how scared someone should be in handling the substance in question, especially if the number is more than one. Though the description is vague, this number could show how easy it is to cause ''some'' kind of reaction of a terrifying magnitude with this substance.
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
Know your extended NFPA hazard diamond:

Flammability: 0 (top)

Health hazard: 4 (top-left)

Instability/reactivity: 2 (top-right)

Number of digits in the street value ($/gram): 2 (left)

(Special hazard) (center)

How much of a hassle it is to dispose of: 4 (right)

Number of federal agencies who want to know if you have any: 3 (bottom-left)

How many times you have to scrub your hands after touching it before they stop smelling weird: 1 (bottom-right)

Number of times it's caused one of those terrifying lab accidents that chemists tell scary stories about late at night: 2 (bottom)

{{comic discussion}}

Talk:2623: Goofs

2022-05-23T16:52:29Z

Sollyucko: xkcd number URL works for me

I'm getting a 404 error when I try to go to the comic by number. But it shows up on the main xkcd.com home page. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 16:39, 23 May 2022 (UTC)
: https://xkcd.com/2623/ works for me. [[User:Sollyucko|Sollyucko]] ([[User talk:Sollyucko|talk]]) 16:52, 23 May 2022 (UTC)

Talk:832: Tic-Tac-Toe

2022-03-24T12:18:56Z

Sollyucko: /* What would happen if BOTH players used the chart? */ add code formatting

This is all wrong. The second move for X, unless O blocked it already, or started off in the centre should be the lower right corner. That way, O will use the centre to block, and then X goes in a third corner, thus sealing the game.[[Special:Contributions/76.29.225.28|76.29.225.28]] 04:59, 23 July 2013 (UTC)
:Can you tell which situation you mean? If X starts at 7 and O does not go to 5, then X s a win with the described tactic. There might be other ways to win, but I don't think that matters. --[[User:Chtz|Chtz]] ([[User talk:Chtz|talk]]) 09:11, 23 July 2013 (UTC)
::Playing as X, you start in the upper left corner. O plays in any square other than the lower right corner (They ''might'' be able to block if they play the centre, depending on whether they anticipate this move). Then, when O blocks the centre, you play the upper right or lower left corner, depending on where O has played before, thus making it impossible to block because they only get one move. The only time this ''ever'' fails is when O knows what X is doing after the ''first'' move.[[Special:Contributions/76.29.225.28|76.29.225.28]] 19:57, 23 July 2013 (UTC)
:::If it goes X7, O5, X3, then O must play anywhere but in a corner next (result is symmetric) X has to block and O can hold a draw. Just see the ''Map for O'' part. --[[User:Chtz|Chtz]] ([[User talk:Chtz|talk]]) 21:40, 23 July 2013 (UTC)
::::I don't know the numbers for the squares. There are only nine of them. Could we just refer to them by their positions relative to the rest of the board?[[Special:Contributions/76.29.225.28|76.29.225.28]] 21:44, 23 July 2013 (UTC)
:::::There is more than one way to win. Although X3 does win, as you say, the comic shows an alternative which also has a 100% chance of success. [[User:Jacky720|That's right, Jacky720 just signed this]] ([[User talk:Jacky720|talk]] | [[Special:Contributions/Jacky720|contribs]]) 00:34, 12 February 2019 (UTC)

There is an error in the drawing when starting with (numpad coordinates) X7, O9, X1, O4, X3: Both O5 and O6 have the same picture. --[[User:Chtz|Chtz]] ([[User talk:Chtz|talk]]) 09:11, 23 July 2013 (UTC)
:There is also an error in X7-O1-X9-O8-X3, in which O2 and O5 have the same picture. [[Special:Contributions/108.162.216.63|108.162.216.63]] 02:46, 7 January 2016 (UTC) (And yes, I am reviving a thread from three ago. Happy 2016.)

'''Tic-Tac-Toe''' is just a stupid simple game, Randall jokes about '''that'''. As the title text says "...waiting for your opponent to make a mistake". And the picture is just a part of this joke.--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 22:04, 23 July 2013 (UTC)

I just don't want to analyze both maps, but I had a college assignment that made me look into Tic Tac Toe strategy, and I think that the explanation should start with "Each map shows every possible combination of moves which will result in that side not losing.". [[Special:Contributions/108.162.212.206|108.162.212.206]] 23:40, 14 January 2014 (UTC)

The quote from War Games is "The only way to win is not to play", and it refers to the game Thermonuclear War, not Tic-Tac-Toe (although that was played earlier in the movie). I don't think the title text was based on this quote, but is only coincidentally similar. {{unsigned ip|108.162.249.215}}

: With all due respect, I think the probability that the title text does not reference the movie War Games is so low as to be effectively zero. BTW the whole premise of the resolution of the movie (spoiler alert) is that by playing Tic-Tac-Toe the AI learns the futility of unwinnable 'games'. It then applies this learning to the very real scenarios of thermonuclear war and, realising the futility, stops. [[User:Plm-qaz snr|Plm-qaz snr]] ([[User talk:Plm-qaz snr|talk]]) 08:20, 16 August 2014 (UTC)

:: I think both of you are right in some way, so I fix the text that it do refer to the movie {{w|WarGames}} but to the AI's opinion on the nuclear warfare "game" after learn the concept of unwinnable through Tic-Tac-Toe. [[User:Arifsaha|Arifsaha]] ([[User talk:Arifsaha|talk]]) 15:58, 12 September 2014 (UTC)

Those diagrams don't depict '''every possible''' situation (e.g. "X2, O8" is missing) {{unsigned ip|162.158.90.222}}

Know any good (but not perfect) tictactoe sims? [[User:SilverMagpie|SilverMagpie]] ([[User talk:SilverMagpie|talk]]) 03:26, 18 April 2017 (UTC)

== Could someone please explain how to read the comic? ==

I feel like I should get it, but I don't know how you're supposed to read this, and the explanation doesn't help. Like, if you want to put down an X somewhere, what do you look at to see what happens in that situation? [[User:Mynotoar|Mynotoar]] ([[User talk:Mynotoar|talk]]) 13:35, 6 April 2016 (UTC)
:I hope you understand what I added. [[User:Demro|Demro]] ([[User talk:Demro|talk]]) 17:38, 6 April 2016 (UTC)
:You do what the comic tells you. The comic isn't designed for you to disobey it. [[User:Jacky720|That's right, Jacky720 just signed this]] ([[User talk:Jacky720|talk]] | [[Special:Contributions/Jacky720|contribs]]) 00:36, 12 February 2019 (UTC)

== What would happen if BOTH players used the chart? ==

I can't do this myself because I'm bad at keeping track of stuff [[Special:Contributions/172.68.142.167|172.68.142.167]] 17:06, 10 December 2019 (UTC)
:Every game would end in a tie. [[Special:Contributions/162.158.193.144|162.158.193.144]] 14:30, 11 May 2020 (UTC)
Every game would go like this: (it makes sense in edit)

<pre>
X—- X—- X—- X—- XX- XXO XXO XXO. XXO
——- -O- -O- -O- -O- -O- -O- OO- OOX
——- ——- —-X -OX -OX -OX XOX XOX XOX
</pre>

:I added monospace, whitespace-preserving formatting using <pre><pre>...</pre></pre> [[User:Sollyucko|Sollyucko]] ([[User talk:Sollyucko|talk]]) 12:18, 24 March 2022 (UTC)

619: Supported Features

2019-04-24T22:37:37Z

Sollyucko: /* Explanation */ Disambiguated link

{{comic
| number = 619
| date = August 5, 2009
| title = Supported Features
| image = supported_features.png
| titletext = I hear many of you finally have smooth Flash support, but me and my Intel card are still waiting on a kernel patch somewhere in the pipeline before we can watch Jon Stewart smoothly.
}}

==Explanation==
This comic is a reference to {{w|Linux}} builds adding support and features that will not appeal to the majority of desktop computer and Linux users. Cueball has created a patch that allows support for processors with 4,096 cores, even though most computers have only 8 cores or fewer. He considers this to be more worthwhile an endeavor than full-featured {{w|Adobe Flash|Flash}} support, which was the most common way to present videos or animations on websites at the time when this comic was published, five years before the first official release of {{w|HTML5}}. Flash movies are known for their bad performance and high consumption on CPU power compared with other movie formats. Cueball's friend is uninterested in the 4,096-core-processor fix, and only wants to know if it will help him with Flash video.

However, as of 2013, there are commercial computer systems that can be actually configured up to 2,048 cores (4,096 threads), e.g. [http://www.sgi.com/products/servers/uv/models.html SGI UV 2000]. Linux powers 95% of the world's supercomputers, so while Flash video on desktop Linux would directly affect more people, the high performance computing industry relies on and actually funds Linux development. It should be noted that GNU/Linux now supports flash via {{w|Gnash_(software)}}. The first stable release was February 15, 2012; over two and a half years after this comic was written.

The title text mentions the "American political satirist, writer, director, television host, actor, media critic, and stand-up comedian" {{w|Jon Stewart}} which further refers to his famous American late night satirical television program ''{{w|The Daily Show}}''. The show is also available on the internet ([http://www.thedailyshow.com/ www.thedailyshow.com]), presenting the shows on Flash videos.

==Transcript==
:[Cueball and a friend holding a laptop standing together.]
:Cueball: It took a lot of work, but this latest linux patch enables support for machines with 4,096 CPUs, up from the old limit of 1,024.
:Friend: Do you have support for smooth full-screen Flash video yet?
:Cueball: No, but who uses ''that?''

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Multiple Cueballs]]
[[Category:Linux]]

Talk:416: Zealous Autoconfig

2019-03-04T15:29:59Z

Sollyucko: Improved comment's formatting

I have my network autoconfig set up to run a rainbow table attack if there's a password on the network. Wifi everywhere is great. [[User:Davidy22|Davidy22]][[User talk:Davidy22|<tt>(talk)</tt>]] 15:05, 1 November 2012 (UTC)
:That's superb! [[User:Suspender guy|Suspender guy]] ([[User talk:Suspender guy|talk]]) 17:12, 22 December 2015 (UTC)

But how would the school know about the Lenhart children if Mrs. Roberts deleted the students table? {{unsigned ip|184.11.73.88}}}
:I say it'd be a liveware attack. A voice-call from the application, with in-built speech-synthisis and speech-recognition capabilities, requesting information from the school secretary him/herself. Probably a Black Hat construction. Or Hartigan (/whoever) from the Leverage series... ;) [[Special:Contributions/178.107.249.215|178.107.249.215]] 23:43, 17 June 2013 (UTC)

I think Miss Lenhart must be the Lenhart children's paternal aunt. Their mother is most probably Mrs. Lenhart. [[User:Xhfz|Xhfz]] ([[User talk:Xhfz|talk]]) 02:20, 14 October 2013 (UTC)

When I saw "Ctrl + C" my first thought was "copy." It's the dumb thing about windows and every implementation that uses that. [[Special:Contributions/108.162.245.217|108.162.245.217]] 14:02, 9 July 2014 (UTC)

It gets worse! I regularly use Konsole, where ctrl-c cancels things; ctrl-shift-c copies, but then I start using ctrl-shift-c in Chrome and end up debugging web pages instead of copying text. GAH! {{unsigned ip|141.101.70.157}}

A similar concept to [[538: Security]]. [[User:Shanek|Shanek]] ([[User talk:Shanek|talk]]) 12:29, 1 May 2015 (UTC)

Believe it or not, you can use ctrl-insert to copy on almost any linux or windows program. Shift-delete is cut and shift-insert is paste. --[[User:PsyMar|PsyMar]] ([[User talk:PsyMar|talk]]) 13:13, 1 May 2015 (UTC)
: I think the difference is WordPerfect vs Word short-cuts, both are supported both for historic reason and to support both left and right handed users with a mouse in their primary hand.[[Special:Contributions/162.158.133.114|162.158.133.114]] 01:45, 23 December 2015 (UTC)

:: [[1479|XKCD 1479]] right here.[[Special:Contributions/108.162.237.124|108.162.237.124]] 17:49, 9 May 2015 (UTC)

I think there's also a pun on "acquired". A network address can be acquired, but when children are acquired it means something quite different. (However, in context they are both required to connect.) [[Special:Contributions/198.41.238.32|198.41.238.32]] 11:22, 27 November 2015 (UTC)

Talk:612: Estimation

2019-02-05T00:27:57Z

Sollyucko: Fixed formatting and grammar

I've experienced this more strongly while installing programs rather than transferring files, and the "connection lost" part is not exclusively from Microsoft. [[Special:Contributions/108.162.212.196|108.162.212.196]] 22:06, 3 January 2014 (UTC)

I think there needs to be some explanation on what "per-file overhead" is, for those who don't know - myself, for instance. [[User:Codefreak5|Codefreak5]] ([[User talk:Codefreak5|talk]]) 22:12, 17 July 2014 (UTC)

: It's the time spent looking up the destination folder, adding an entry for the file in that folder (a folder is an index of file names and locations, not a physical division of the disk), and recording metadata such as the creation date and owner. Basically, it's the time it would take to move the file to a different folder on the same disk, minus the time it would take to delete the file (bypassing the Recycle Bin). [[User:Promethean|Promethean]] ([[User talk:Promethean|talk]]) 06:08, 18 July 2014 (UTC)

In fairness, I wonder if we should mention that this is a really hard problem to solve. it's only a little bit easier than the extremely hard problem given in [[1425: Tasks]]. [[User: 00N8]] ([[User talk:00N8|talk]]) 00:02, 5 March 2018‎ (UTC)