explain xkcd - User contributions [en]

Talk:899: Number Line

2023-11-30T00:07:17Z

Plushiefan4111:

Where does sqrt(-1) go? [[Special:Contributions/67.78.183.206|67.78.183.206]] 19:07, 2 January 2013 (UTC)

:It goes up (literally above 0). A number line can be extended to a complex plane with sqrt(-1) as the unit of measurement in the vertical direction. Or at least, that's where it actually goes. I don't know where Randall would put it. [[Special:Contributions/75.69.96.225|75.69.96.225]] 01:04, 5 March 2013 (UTC)

I'm sorry...are you indicating the ACTUAL location for an IMAGINARY number? {{unsigned|‎74.213.186.41}}

Yes, that's exactly where it is (up to switching clockwise for counterclockwise). There is nothing strange about providing a location for imaginary or complex numbers, the location described is logical, and the adjective 'imaginary' is an artifact of nomenclature and nothing more.[[Special:Contributions/173.48.140.216|173.48.140.216]] 20:40, 30 March 2013 (UTC)

In fact, complex numbers are nearly more real than real ones! Complex analysis really opened my eyes to how much "stepping out" can help in solving problems. The complex notion of analyticity yields fruit in real analysis. Extensions to hypercomplex numbers are weirder, however. --[[User:Quicksilver|Quicksilver]] ([[User talk:Quicksilver|talk]]) 20:27, 17 August 2013 (UTC)

Analyticity must be an imaginary word, and therefore would be found one unit directly above any dictionary. [[Special:Contributions/50.203.89.169|50.203.89.169]] 14:19, 9 October 2013 (UTC)
:Oh my god, I can't believe how hard I laughed at that. Would an imaginary friend actually be above you then? I'm going to use that sometime. [[Special:Contributions/108.162.219.61|108.162.219.61]] 21:25, 24 April 2014 (UTC)
:"I'm sorry, you have reached an imaginary number. Please rotate the phone by 90 degrees and try again."[[Special:Contributions/141.101.98.250|141.101.98.250]] 17:01, 21 October 2017 (UTC)

Is unexplored a map reference? [[User:Halfhat|Halfhat]] ([[User talk:Halfhat|talk]]) 17:53, 13 January 2014 (UTC)

Note that the digits 5 and 6 do not show up on any of the numbers in the comic, reinforcing the fact that the integers 5 and 6 are unexplored. [[User:Blitzer|Blitzer]] ([[User talk:Blitzer|talk]]) 02:34, 15 May 2014 (UTC)
:So the 5th digit of pi can not be known either? [[User:Tharkon|Tharkon]] ([[User talk:Tharkon|talk]]) 03:56, 12 July 2014 (UTC)
:: The ''wha''th digit of pi? [[Special:Contributions/108.162.215.119|108.162.215.119]] 01:59, 1 January 2015 (UTC)
Thank God (or someone else, I'm not choosy) that the SCP link here still works. The rest of the site's gone private. {{unsigned ip|108.162.250.223}}

It appears that Wikipedia had noticed the implications of the title text here. The message now says that it might never be complete, but can be expanded with reliably sourced articles. I'm not 100% sure it's due to Randall's involvement, but I like to think so. --[[Special:Contributions/141.101.104.17|141.101.104.17]] 22:01, 9 December 2014 (UTC)

I am not American, but the linked Wikipedia Article does not support the claims about president's day being observed between the 2 birthdays of Washington and Lincoln in general, but just that in some states Lincoln is also referenced on that day. Even if it was put as a day between these birthdays by definition and on purpose, I do not see the reference here... Especially as this number is given as specific, unlike presidents day, which can occur in a range of days... Someone who knows more of American culture, and also what "observed" (which would link it to holidays....) can mean in English language please revert this. --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 12:41, 18 September 2019 (UTC)

The link to "bleem" does not work for me, but the word can be found in Urban Dictionary. ——[[Special:Contributions/172.69.63.161|172.69.63.161]] 02:12, 21 August 2020 (UTC)

While 8 is not the "largest even prime", 9 is in fact the ''lowest odd composite'' number. So 8 is the largest in the unbroken line of natural numbers that are even ''or'' prime (or whatever 1 is). [[Special:Contributions/141.101.76.205|141.101.76.205]] 10:48, 18 January 2023 (UTC)

Surely Gird is a reference to Bleem and to the philosophical concepts of Grue and Bleen? Just as they derive from Blue and Green, so we would have Bird and Gleem. [[Special:Contributions/172.71.98.86|172.71.98.86]] 20:33, 29 November 2023 (UTC)

1 pixel <nowiki>~</nowiki> 0.012
start of unexplored zone <nowiki>~</nowiki> 4.381
end of unexplored zone <nowiki>~</nowiki> 6.714
length of unexplored zone <nowiki>~</nowiki> 2.333
coincedence? [[User:Plushiefan4111|plushie fan]] ([[User talk:Plushiefan4111|talk]]) 00:07, 30 November 2023 (UTC)

Talk:Blue Eyes

2023-11-22T15:47:23Z

Plushiefan4111:

Is it really incomplete on the grounds that Joel hasn't be identified? Explanations of comics 57-59 leave no more explanation of "Scott" than that he appears to be Randall's friend. The fact that we don't have a last name for him doesn't make either [[Scott]] or those comic explanations incomplete. Similarly, not have a full identifier for "Joel" in this one doesn't, in my opinion, warrant an incomplete tag. I'm removing the tag. If anyone object, revert it. [[User:Djbrasier|Djbrasier]] ([[User talk:Djbrasier|talk]]) 19:22, 22 May 2015 (UTC)

The proof for this puzzle is incomplete, if not wrong. The theorem is too weak, it should be: "Theorem: N blue eyed people with Nth order knowledge of all N people being logicians, N people having blue eyes, and any blue eyed person will leave as soon as possible after deducing they have blue eyes, will be able to leave on the Nth day." This may seem pedantic, but it really gets to the heart of the problem, which is trying to illustrate the use of orders of knowledge. In the theorem as stated, just N blue eyed people will leave on the Nth day, the proof for the inductive steps does not hold. You need to further assume that the person is able to deduce the hypothesis (which should be proven). In other words, you say X-1 people would leave on the (X-1)th day by hypothesis, so the Xth person knows he can leave on the Xth day. But you did not prove that the Xth person can actually deduce this, namely that he has all the information necessary to do so. In the correctly stated hypothesis, you then need to show that N + 1 people with (N+1)th order knowledge of all those things can deduce that the N people would leave if it was just them, and further that N+1 people have (N+1)th order knowledge of all these things. This is very important, and holds true (Since N+1th order knowledge is equivalent to knowing the N people have the Nth order knowledge necessary to fulfill the hypothesis, and by symmetry if the N logicians can figure it out the (N+1)th can too. Also, they have (N+1)th order knowledge of people leaving as soon as they can and everyone being a logician since in the proper statement of the puzzle it should be noted this is common knowledge, and the guru makes the knowledge of someone having blue eyes common knowledge.). Then you have a full proof, since you have now included that they can actually deduce the inductive step. Again, this may seem pedantic, but is really necessary both to be correct and as it illustrates the key of the puzzle, namely the guru gives 100th order knowledge of someone having blue eyes (this is the main problem people have, realizing the concrete piece of information the guru gives). [[User:Jlangy|Jlangy]] ([[User talk:Jlangy|talk]]) 00:29, 9 July 2015

What I don't follow here is that there's no clarification that the Guru is talking about someone different each time. Just because she says "I see someone with blue eyes" N times doesn't mean that there are N people with blue eyes; she could be talking about the same person every time, or each of two people half the time, etc. Can anyone clarify this?
Thanks - [[Special:Contributions/108.162.218.47|108.162.218.47]] 13:20, 28 October 2015 (UTC)

(EDIT: Observe the process of comprehension in action...or don't? I've been thinking about my own brain, with itself, long enough for one day, I'm tired.)
So, maybe I am indeed just "dumb", as the wiki insists. Clearly, I do not have a perfect understanding of formal logic. But frankly, my read of this puzzle is that "formal logic" just enables you to jump to ridiculous conclusions.
Let's theorize a simpler version of this puzzle. There are now only two people besides the Guru on the island, both with blue eyes. We'll call them Bill and Ted (totally bogus, I know). No matter how logical Bill and Ted might be, when Bill hears the Guru say "I see a person with blue eyes" to himself and Ted, and Bill has seen Ted's blue eyes himself, why would Bill assume anything about his own eye color? It would seem to Bill that Guru was just talking about Ted's eyes, and Ted would believe the reverse. Even knowing* that Ted would leave that night if Ted deduced he had blue eyes too, I still don't see why Bill would jump to the conclusion that the Guru was talking about him - he remains in the dark, as does Ted, and neither of them can be any more certain of anything than they previously were. Adding 98 more blue-eyed people, let alone doubling the island's population with irrelevant brown-eyers, hardly reduces the confusion.
* This was the point at which I began to think I had understood it, but then I became unsure again. Like I said in the "edit", my brain is tired.
--So, that settles it, I do not understand how the puzzle can be true, and I'm not convinced that it actually is. Knowing Randall is, in general, smarter than me...I still do not have the ability to completely accept that he's always right, or that I'm always wrong to ignorantly question his rightness. I have long maintained that certain well-respected "systems of knowledge", of which formal logic is a textbook example, have been respected too well for too long for not-good-enough reasons. To me, they seem to be founded on an assumption which is itself founded on nothing. I'm not trying to insult Randall or anyone else, I'm just utterly failing to comprehend. I will appreciate if anyone else attempts to educate me on the subject, but I may prove an intractable student, since I am unable to extend much faith or trust (or even, on a day where my mood is worse than today, the moderate degree of politeness as I've already managed) to a teacher. [[Special:Contributions/173.245.54.52|173.245.54.52]] 19:18, 30 October 2015 (UTC)

In your simplified version of the puzzle, Bill sees Ted has blue eyes. 
Here's Bill reasoning: 
- Either my eyes are blue or not. 
- If my eyes are not blue, then Ted knows that his eyes are blue, because the Guru said at least one of us has blue eyes, and he'll leave the island tonight. 
- Let's wait. If Ted doesn't leave tonight, that means he doesn't know his eyes are blue, and therefore my hypothesis is false. 
When Bill sees Ted doesn't leave that night, he can deduce that he has blue eyes. 
Ted can do the same reasoning. 
After that first night, both will know they both have blue eyes. 
--[[Special:Contributions/108.162.228.5|108.162.228.5]] 14:09, 14 December 2015 (UTC)

;Superrationality

The solution relies on the fact that "at least 1 blue" is new information which triggers a cascade.

Wouldn't the entire population of the island be able to conclude that everyone else on the island knows there is at least 1 blue eyed individual already?

For example, every person on the island will see at least 99 blues and 99 browns. From this, they can assume that everyone else on the island can see at least 98 blues and 98 browns. Of course, the actual numbers will differ, but 98 is the lower limit for all perspectives.

A blue will see 99 blues and 100 browns, so he will assume that all other blues can see at least 98 and all browns can see at least 99 blues. Similar logic for a brown or any observer.

[[User:Flewk|Flewk]] ([[User talk:Flewk|talk]]) 09:26, 26 December 2015 (UTC)

The solution here is different to Randall's solution, and I think is actually incorrect for two reasons that add confusion and prevented me from understanding the solution until I'd thought about Randall's solution and realised these are actually different.
* It seems to falsely presume that the Guru is speaking to them each day, when this is explicitly not the case in the puzzle.
* I also believe it is incorrect to state that the brown-eyed people can be disregarded. The solution is actually dependent on a *combination* of hypothesis testing and on theory of mind; not just one or the other. It matters that everyone is also thinking about what the brown-eyed people around them must be thinking, otherwise you can't explain why mistakes will not happen with brown-eyed people getting on the ferry when they're not supposed to, and screwing up everybody else's logic.
- If you're on the island and you have blue eyes, there are two hypotheses: either there are 99 people with blue eyes or 100. If there are 99, then everyone one of those 99 people is thinking "either there are 98 people with blue eyes, or there are 99" (and therefore you do not have blue eyes). Blue-eyed people also know that if there are 99 of them, then the brown-eyed people are thinking, "Either there are 99 blue eyed people, or 100." If there are 100, then the brown eyed people are thinking, "Either there are 100, or 101". To summarise, blue eyed people are deciding between 99 or 100, and presuming that other blue eyed people are either suspecting there could be 98/99, or 99/100, while presuming that brown-eyed people are either suspecting there are 100/101, or 99/100.
- If there are 99, then blue-eyes are thinking 98/99, and brown-eyes are thinking 99/100. Blue eyes will plan to leave if the 98th day passes and nobody has left, brown-eyes will plan to leave if the 99th day passes and nobody has left.
- If there are 100, then blue-eyes are thinking 99/100, and brown-eyes are thinking 100/101. Blue eyes will plan to leave if the 99th day passes and nobody has left, brown-eyes will plan to leave if the 100th day passes and nobody has left.
- So you know that if you have brown eyes, you'll watch all the blue-eyes leave on the 99th day. And you know that if you have blue eyes, you'll watch all the brown-eyed people hold back in case their day is the 101st. If you're allowed to leave, there will be no situation where brown-eyed people mistakenly leave on the 100th day, thus confusing things. If you're not allowed to leave, there'll be no reason for you to mistakenly make an attempt to leave on the 99th day.
- Thinking about this fact - what the brown-eyed people are thinking - also reveals why the Guru's comment matters, and adds information, even though it should seem to most people as if no information is being added (because they can all already see that blue-eyed people exist). I think this is a key part of why the problem is so tricky. [[Special:Contributions/108.162.249.155|108.162.249.155]] 07:42, 10 March 2016 (UTC)

The new information the guru gives is nothing more than a common marker (the day of the announcement) to use as a starting point for counting days. Before the announcement, being unable to communicate with each other, they were unable to coordinate a means of figuring out their own eye color.
[[Special:Contributions/172.68.59.105|172.68.59.105]] 21:52, 22 September 2016 (UTC)

That's wrong. In that case the browned eyed people would do the same, but they can't.

What I'd like to know: If there were 100 blue-eyes, 200 brown-eyes, 300 grey-eyes and 400 red-eyes, and the Guru says "I don't see anyone with a unique eye color", would that permit everyone to leave (except the Guru herself) using the same logic? Meaning the blue-eyes leave again on day 100, the brown-eyes on 200, the grey-eyes on 300, and the red-eyes on 301.

I think it would actually be days 99, 199, 299, and 300, because the 'what if there were only two blue-eyes' case would be solved on day 1 - i.e. both would see only one blue-eye and deduce that they are also a blue-eye, and both would leave - so everything gets moved up by one day.[[Special:Contributions/141.101.76.16|141.101.76.16]] 13:52, 4 January 2018 (UTC)

This was bugging me today - specifically the guru doesn't seem to actually give any information, because with at least 3 blue-eyed people, everyone on the island knows that the guru sees people with blue eyes, and also everyone knows that everyone knows the guru sees people with blue eyes. So for a while I thought the brown-eyed people must have as much information as the blue-eyed people, and either they both could leave or neither could leave.

:Consider this, if there were only 2 people with blue eyes, everyone would know that she sees someone with blue eyes beforehand, but everyone wouldn't know that everyone knows that, as the 2 people with blue eyes would not know if the other person with blue eyes can see anyone with blue eyes, so the 2 people with blue eyes would deduce they have blue eyes when the other person doesn't leave the first day, as themselves having blue eyes would be the only explanation for that person not leaving the first day. The dispute here is if you can extend that chain of reasoning past there being only two people. After all, with 3 people, as you said, everyone knows that everyone knows that she can see someone with blue eyes already, but when you consider the people who have blue eyes, everyone doesn't know that everyone knows that everyone knows that, even though each individual would personally know that everyone knows that everyone knows that, as the people with blue eyes know that if they don't have blue eyes, then the 2 people with blue eyes they see would only see one person with blue eyes and know that the Guru can see someone with blue eyes, but wouldn't know that the other person with blue eyes knows that. But would everyone follow such a chain of logic and make assumptions based one people not leaving based on days with significantly lower numbers passing that they personally know that no one would expect a possibility of anyone leaving on? This whole question is hinged on people following perfect logic that is based on other people following the same perfect logic that would predict this. If perfect logic necessitated people leaving in such a manner, then everyone would know the rest of the people would follow this rule and the solution would hold, but if it didn't, then it would be just as consistent if no one left. This is basically circular reasoning about using logic to predict the actions of people who are acting according to the same reasoning as yourself. Both this answer being correct and it wouldn't wouldn't violate pure logic based on a system of reasonable seeming logical principles and the terms of the question.--[[Special:Contributions/172.70.127.94|172.70.127.94]] 04:35, 12 October 2022 (UTC)

After a bunch of reading and testing possibilities I think I've actually figured it out now and why only blue-eyed people leave, but I haven't seen an actual good explanation for it yet, so here's my explanation: The information the guru gives is that, NO MATTER HOW MANY BLUE-EYED PEOPLE THERE ARE, they can figure out they have blue eyes. It is important that it is possible for blue-eyed people to be able to solve it for EVERY number, even if everyone knows there is more people than that number (basically because, everyone doesn't know that everyone knows there is more than that number and there's a gap in their logic without knowing that). If there is any number for which blue-eyed people cannot figure it out, then any solution (namely, what I thought before testing possibilities) would require that there is a number N of blue-eyed people that cannot leave, but a number N+1 of blue-eyed people that can leave. This is self-contradicting though. If N blue-eyed people can't figure it out, than N+1 people (regardless of eye color) can't get meaningful information from the action of those N blue-eyed people. And since they can't get meaningful information from N people's actions, N+1 people can't tell if there are N people and that individual is not blue eyed, or N+1 people and they are blue-eyed. It would be logically incorrect for them to assume an eye color at that point, which means they don't know if they can leave, and then N+2 people are similarly unable to get meaningful information from N+1 people's actions, and so on. Because a single blue-eyed person cannot figure it out, more blue-eyed people (regardless of number) cannot make any assumptions without additional information. Then the guru effectively states a single blue-eyed person could leave immediately (which means 2 could leave the next night confidently, and thus 3 the next, and so on in an UNBROKEN chain). Kejardon - [[Special:Contributions/162.158.214.82|162.158.214.82]] 11:15, 9 January 2020 (UTC) (I doublechecked and edited/corrected my post kind of at the same time, so your reply doesn't make sense anymore, sorry Lupo. Feel free to delete these two sentences if you change/delete your reply)
:You bring up 2 points. First about the common marker. This is true, but it contains more information than "start counting from today," because every blueeyed person has 2 scenarios: With 99 blue eyed people and with 100. The numbers are not important, and it would also be needed with 1,2,3,etc. blue eyed people. The point about the brown eyed people: The brown eyed people have no way to conclude (remember, they are "perfect logicans" and their task is to figure out, not to make an estimated guess) that their own eyes are in fact brown, and not red, or green just like the Gurus. If the guru just said: "Start counting", then noone woul leave at any given night. --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 11:05, 9 January 2020 (UTC)

I figured this out in less than a minute... there were so many warnings about the solution being convoluted that I thought I couldn't possibly have it right. It's not really that confusing and I've seen waaaaaaay harder logic problems.

This image is listed under "My Hobby" for some reason, despite not even being a comic, let alone a "My Hobby" comic. [[Special:Contributions/162.158.111.151|162.158.111.151]] 00:58, 9 September 2019 (UTC)How sign edit

It's been years and I stumbled back across this post, and I think I finally understand what has been bothering me.
The examples always go up to 3 blue-eyed people, and then we just assume that it follows a the pattern, but a pattern has to be confirmed to all states to be a proof. This is why Fermat's last theorem remained unproven for years even though we had solved the N =1,2,3 cases. To expand on the biggest criticism, what new information does the guru give? 
-Someone learns something : Only true from the perspective of someone who sees no-one with blue eyes. 
-Someone could learn something : Only true from the perspective of someone who sees exactly one person with blue eyes. 
-No-One can learn anything : True from the perspective from someone who sees multiple people with blue eyes. 
This is where the problem occurs, because this only resolves with 3 blue-eyed people otherwise we don't learn anything, but how we acknowledge that we don't learn anything matters. 
-Everybody must know that no-one can learn : True from the perspective of people who see people who must see multiple people with blue eyes. 
-Everyone must be aware of the previous fact : I guess it does go on... 
In the end, it's all about the meta-data. 
I know, you know, they just don't have any proof... 
Crow --[[Special:Contributions/108.162.245.65|108.162.245.65]] 00:12, 30 September 2021 (UTC)

Apostle's Solution: The first person to look into the water and see their own reflection. For a logic puzzle, people seem to forget about the situations actual logic. {{unsigned ip|162.158.74.213}}
:What part of: "There are no mirrors or reflecting surfaces" do you not understand? --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 09:54, 18 May 2020 (UTC)
:What can you even do to an island to remove all reflecting surfaces? Absolutely everybody would leave the the night after the weather is good enough to see their reflection in the sea.
::Then the weather is never clear enough to see their reflections. It's equally valid to question why the ferryman would only free people who knew their eye color, or whether some people would want to stay on the island instead of leaving...and far ''more'' valid to point out that perfectly logical beings like the problem describes ''don't exist''. If you're not willing to suspend your disbelief enough to accept the premise of a logic puzzle, that's fine, but it's no more ridiculous than suspending your disbelief enough to accept that hobbits and wizards exist in Middle Earth. [[User:GreatWyrmGold|GreatWyrmGold]] ([[User talk:GreatWyrmGold|talk]]) 03:29, 17 July 2021 (UTC)

If there are N islanders with blue eyes, every person sees at least N-1 blue eyed persons. Person A with blue eyes seeing N-1 blue eyed persons has to consider the possibility that there might be a person B who only sees N-2 blue eyed people and acts accordingly. However, everyone in that scenario will agree that it is absolutely impossible for anyone to see N-3 or less blue eyed people and that case cannot possibly be considered by anyone. Therefore the induction step is invalid and nobody will ever leave the island for N>3. [[User:Boopers|Boopers]] ([[User talk:Boopers|talk]]) 18:07, 15 October 2021 (UTC)

If a person B only sees N-2 blue eyed people, then surely they have to consider the possibility of a person C who only sees N-3 people. Sure, person B doesn't actually exist in this scenario, but you'd have to consider that person A would have to consider what a hypothetical person B would have to consider. It's turtles all the way down. [[Special:Contributions/172.70.110.171|172.70.110.171]] 00:17, 19 October 2021 (UTC)

No. It doesn't turtle down and nobody inside the scenario is free to consider any hypothetical persons. Instead, everything that one of the persons may consider about another person on the island has to be consistent with his observations of the persons who are actually there. And that breaks down at person C in my example. Yes, person B from the example does not exist, but the important thing that was being missed is that person C can be proven by everyone involved to be impossible which is not the case for B.
Lets just consider the scenario with 4 blue eyed persons, the smallest number where the argument breaks down. Now lets choose two completely arbitrary persons A and B (And I really mean completely arbitrary - doesn't even require for A and B to be different persons). It can be shown that A knows that B sees at least 2 blue eyed persons. Now since A and B were chosen arbitrarily, that means that every person on the island knows that every person on the island sees at least 2 blue eyed persons. This observation is of great importance, because it contradicts an invalid assumption implicitly made in the induction step. The induction step relies on the incorrect assumption that at the end of day N knowledge is gained that the number of blue eyed persons is larger than N. That assumption works out well for 2 or 3 blue eyed persons, but completely breaks down at 4 blue eyed persons right at day 1, since we have shown that everyone is already aware that there is more than 1 blue eyed person before the end of day 1.
This invalid assumption is extremely well hidden in the presented proofs. In the "Intuitive Proof" section, it is hidden inside the wrong assertion that the simplified problem supposedly is equivalent to the original one when it is absolutely not. And in the "Formal Proof" section, the islanders are just being assigned a reasoning without there being a proof to why they would reason this way. Of course following this flawed reasoning will lead to the desired result, but if they were the perfectly logical thinking people like the problem described, they wouldn't just miss the fact that there are cases where no knowledge can be gained on day 1 and therefore on any of the following days, and they would incorporate that into their reasoning. [[User:Boopers|Boopers]] ([[User talk:Boopers|talk]]) 18:31, 13 November 2021 (UTC)

Boopers, let me see if I can convince you it works for n=4 by making it a story. There are 4 blue-eyed people on the island; Arnold, Boopers (you), Carl, and Denise. You don't know your eye color, but have always thought of yourself as a brown-eyed person, and if you had to guess, you would guess you have brown eyes; after all, almost everyone does. When you hear the guru speak, you think that since there are only 3 blue-eyed people, A, C, and D. They are dear friends of yours, and you are very sad that after 3 days, you will never see them again. So you have a busy 3 days coming up, since there are things you've put off doing that you must do quickly, before A, C, and D leave your life forever.

A, while a good friend, has a habit of borrowing things and not returning them, and you don't want your stuff going with A on the boat. So you spend day 1 getting A to return your lawnmower, snowblower, and the dozen books he has borrowed over the years and not returned. You get all your stuff back. A good day 1.

While C is a friend, you haven't always treated him well. So day 2 you spend with C, doing whatever you can to ensure he has a good day on his next-to-last day on the island, and apologize to him for the ways you have wronged him in the past. He accepts your apology, and you are pleased that you haven't left things unresolved with your friend who will leave the island forever in 2 days. A great day 2.

On day 3; you confess to Denise (who is married to Arnold) your undying love for her. You've never told her this, out of respect for her marriage, but you've always suspected that your feelings were returned. Now that you will never see Denise or her husband again after noon tomorrow, so there will be no repercussions. To your delight, you discover that your feelings are indeed returned, and you and Denise spend what you think will be your last night together making love until the early morning hours. A perfect day 3. And since A and D are leaving on the boat the next day, and you, with your brown eyes, are staying on the island, probably forever, there will be no repercussions.

The next day, when you know A, C, and D will be leaving at noon, you rise early, and just before noon, you head to the pier, wanting to see Denise once more before she leaves on the noon boat. A, C, and D are of course there too. But to your great surprise, when the "all aboard" is sounding, A, C, and D do not move to get on the boat.

How can this be? What has happened? Again and again you go over the logic that says "if there are only 3 blue-eyed people on the island, they will all leave on day 3" and find it to be ironclad. And you know that your friends A, C, and D are perfect logicians, and can reason the same way you do, and you certainly know that they would never violate the rule that if you know your eye color, you must leave. And yet they remain! It seems impossible! How can this be? Unless...

Does a possibility occur to you to explain their inexplicably remaining on the island? You are certain of your logic that says "*If* there are exactly 3 blue-eyed people on the island, they will leave on day 3". So it must be that there are more than 3 blue-eyed people on the island. But you re-check the eye color of everyone else you can see, and they are all brown. Do you realize what must have happened?

Do you now know your eyes are blue? Do you get on the boat on day 4? [[User:Yp17|Yp17]] ([[User talk:Yp17|talk]]) 19:14, 9 February 2022 (UTC)

I think that helps highlight why the induction as presented doesn't work. Indeed, I believe everyone leaves on the 4th night, and that the Guru provides no information at all -- only a random token which could not have existed before since communication was impossible.

Once the Guru speaks, the solution becomes possible for only the case of blue-eyed people, because only then can every person on the island be sure they are counting the same color. But the content of what she says is meaningless, as everyone already knows what she says. She could have simply said, "Blue eyes", and the same result could be accomplished (I in fact nominate that for a harder form of the puzzle).

Following this, the expected reasoning happens, but there is no reason for it to stop at the time presented. Waiting one day to see if there is one blue-eyed person that will leave is meaningless and completely irrational -- every person on the island can see enough blue-eyed people to know, with certainty, that every person knows there is more than one blue-eyed person. Therefore, waiting that first night is wasted, since the outcome is known with absolute certainty. Waiting must logically begin only on the first day where the outcome is not certain.

To find that day, the relevant metric is the lowest number of blue-eyed people that can be known to exist to every person on the island. That number is 97 -- consider a person A, blue-eyed, calculating the knowledge of another person B, also blue-eyed. (If either are brown-eyed they can mutually estimate more blue-eyed people, so this is the relevant case.) Since A is uncertain of their eye color, they must for the worst case assume it to be brown; therefore, they estimate 99 blue-eyed people, of which B is one, whom therefore sees 98 blue-eyed people in this scenario. B cannot be sure of their own eye color, so they will see 98 blue-eyed people, and when modelling a further person (C, say) following the same logic could conclude they themselves are not blue-eyed and therefore C will only be able to guarantee 97 blue-eyed people (A's model is, A is brown, and B's model is B is brown, so C's model excludes A and B and is uncertain about C.)

Importantly, this does not induct! There is no rational way in the given 100/100/1 distribution for someone to not be certain of 97 people, even though there is a temptation to chase a clear recursive pattern. The reasoning behind it does not hold -- A does not need to worry about B->C->D's model, because no one has that much uncertainty -- it is incorrect to model D, because you can observe everyone's computation at most two steps removed from directly. When establishing a pairwise estimate of the distribution of eye colors, there are only two points of uncertainty -- the observer, and the person being modelled. A knows, with certainty, that there is no situation where someone will model the behavior of another and find a lower bound of less than 97, because even if A is brown-eyed, they know every other person on the island will see at least 98 blue-eyed people, regardless of all other factors.

The salient modelling question is, therefore, only how much "worse" than 98 it can be. One may be tempted to assign another -1 to the new observer who then must assign another -1 to their target, but that is illusory -- in our previous example, the uncertainty with which C considers D is the same uncertainty that A already accounted for, i.e. the uncertainty of the observer. No matter who is modelling who, there is only one observer, one modeled-observer, and one modeled-observer-target. Further extrapolation isn't necessary. Therefore, since A knows they are looking at someone with blue eyes, that person B can conclude that of the 98 people they assuredly see, they must subtract only one more for the worst case -- the estimate of C, who knows not their own eye color. B doesn't need to account for their own eye color, because A already did that in their own uncertainty, and they know that B is blue-eyed -- no matter who they select of the 99 blue eyed people they see, that person will see (at least) 98 blue eyed people, and gives no greater uncertainty than the case where A is brown eyed and they are considering someone else blue-eyed, lowering the bound to 97. It in no circumstances is estimated lower than this.

That means that every knows, with certainty, there are 97 blue eyed people at a minimum, and therefore the first interesting day is the 97th on the "original timeline" -- but that clearly isn't the case, because everyone can already count more than 97 blue-eyed people. Indeed, everyone can count 99 blue-eyed people; it is only in question for each observer whether they are a 100th blue-eyed person, and the chain of reasoning exists to expose that. The worst-case 97 holds only if his own eyes are brown, and another blue-eyed person considers a third blue-eyed person. Since there is no way to communicate, there is no way to improve upon that uncertainty, so that must be the point of first decision:

The first interesting night requiring a decision is establishing whether 97 people have blue eyes, or more than 97 people. This could be known with ceratinty by the original reasoning, which persists until the 97th night. However, everyone knows, with certainty (due to the above) that every night prior to the 97th night will result in no action; therefore the only logical course of action is to begin with the first point of new information. They "start" with the 97th day, and leave on the 100th, for a total of 4 days. [[User:Dokushin|Dokushin]] ([[User talk:Dokushin|talk]]) 07:55, 26 February 2023 (UTC)

:You are 99% of the way there... to explaining why the solution does not work at all. You are absolutely correct that there is no reason for anyone to assume that anyone else would ever assume less than 97 blue-eyed people, and therefore the induction does not carry through. But this means they have absolutely no grounds whatsoever to start making any assumptions about who could possibly figure anything more out and therefore who & when could possibly be getting onto the boat. In the presented scenario, no one ever leaves. It could only be different if the guru spoke about seeing 98 blue-eyed persons. [[Special:Contributions/172.70.85.125|172.70.85.125]] 11:11, 30 September 2023 (UTC)

;Unstated assumption (about motives)
While trying to solve this, I started questioning my assumptions about the motives of the islanders. It turns out my assumptions were correct, but I think they deserve to be explicitly stated:
# Everyone wants to leave the island ASAP.
# An islander only "figures out" their eye color through logical deduction (no guessing or playing the odds)
# The Guru's statement is meant to help others leave the island. (but as stated above, it may not be the optimal means of helping others leave -- "nobody has a unique eye color")
:Regarding the 1st point: Yes, that needs to be stated.--[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 11:37, 9 January 2020 (UTC)
:Regarding the 2nd point: It should be mentioned, but could be implied by the words "figure out" and by the fact that everyone is a "Perfect logican". --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 11:37, 9 January 2020 (UTC)
:Regarding the 3rd point: If it was not meant to help people leave, it would still do the same job. Also the statement from the Guru "nobody has a unique eye color" would be wrong and misleading! In that case everyone would wrongly assume: "I must have green eyes, as otherwise the Guru would have an unique eye color." - The alternative statement "I see noone with a unique eye color" would work. --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 11:37, 9 January 2020 (UTC)

Storming lighteyes (not sorry) [[User:SilverMagpie|SilverMagpie]] ([[User talk:SilverMagpie|talk]]) 17:50, 10 January 2020 (UTC)

;Guru gives synchronizing signal to begin recursive cascade, without which it can’t start.
We might wonder why it is noted that the islanders have been on the island “all these endless years”, but the recursive cascade had never happened. The reason is that There must be a time zero, T0, from which the wait period is defined. Without that discrete starting point, there is no reference point to begin waiting to see who leaves. The Guru provides a starting event, visible (or audible) to all, where they can say “this is T0”, and our deductions can now proceed. So it synchronizes everyone to begin their waits.

I finally got this one, and while this may be repeating others' explanation of "what info does the Guru provide", I'll try another way in the simple way that was MY "aha!"/satori moment in hopes it'll help someone else too:
(A) as others have pointed out, the case of 100 reduces down to 1 (if there were 1 blue-eye, that statement would do it in 1 day, so it cascades for cases of 2, 3 etc.);
(B) once the Guru "triggers" that cascade, you just count the other people with blue eyes, and wait that number of nights; when it hits zero, leave. (It works for 1 (leave that night), for 2, (leave next night), 3 (leave the 2nd night)....)
(C) SO: the Guru saying it the statement is basically "I am hereby "triggering the "Blue-Eye Cascade". It's NOT so much whether ANYONE CAN SEE A BLUE-EYED PERSON - obviously everyone on the island can!

* '''It's the Guru BEING A LOGICIAN, AND TRIGGERING A LOGICAL CASCADE FOR THEM. S/he could've ALSO said BROWN - and THAT would've had the OTHER effect - because that'd have been giving THAT "hint"/"clue" (!!!!!!!)'''
[[User:Abner Doon|Abner Doon]] ([[User talk:Abner Doon|talk]]) 16:12, 16 April 2023 (UTC)

what if there is 1 blue-eyed person on the island outside of houses while the guru is saying that, and everyone else is in houses with their windows and doors shut? [[User:Plushiefan4111|plushie fan]] ([[User talk:Plushiefan4111|talk]]) 15:47, 22 November 2023 (UTC)

2000: xkcd Phone 2000

2023-11-22T14:38:58Z

Plushiefan4111: i dont think you should use "obviously" because what if some people dont know a lot about smartphones? isnt this wiki meant to be accepting of all knowledge levels?

{{comic
| number = 2000
| date = May 30, 2018
| title = xkcd Phone 2000
| image = xkcd_phone_2000.png
| titletext = Our retina display features hundreds of pixels per inch in the central fovea region.
}}

==Explanation==
This is the seventh entry in the ongoing [[:Category:xkcd Phones|xkcd Phone series]], and once again, the comic plays with many standard tech buzzwords, and horribly misuses all of them, to create a phone that sounds impressive but self-evidently isn't to even the most ignorant customer. The previous comic in the series [[1889: xkcd Phone 6]] was released 8 and a half months before this one, and the next comic [[2377: xkcd Phone 12]] was released two years and five months later.

This time, a nonconsecutive version number is used to match the 2000th xkcd comic number. The tagline for the phone says that the marketing team hopes that 2000 still sounds like a futuristic number. It was common for a time to have futuristic science-fiction take place on or around the year 2000 (e.g. 2001: A Space Odyssey, Knight Rider 2000, Death Race 2000, Space: 1999), and many devices marketed in the late 20th century had a "2000" as part of their product name in order to sound futuristic. However, since the year 2000 is decades ago, this is no longer the case. The number 2000 also represents the fact that this is the 2000th xkcd comic. The nonsensical trademarking of xkcd Phone slogans has become even more pronounced: as well as the inapplicable-as-ever copyright symbol, the slogan is listed three times as a {{w|registered trademark}} and twice as an unregistered one – and the second of those trademark signs is itself trademarked.

From the top, going clockwise:

; Dockless

: It was common practice for older standard cellphones (i.e. non-smartphones) to use a docking station for charging. "Dockless" could be a catchy marketing term for wireless charging, or it could simply mean wired charging without a dock.

; Silent

: Most mobile phones have a "Silent" mode in which all ringing and vibration is muted, so the user can receive messages and missed-call notifications in a place that requires silence. This xkcd Phone feature may be a "Silent" mode button, but perhaps the phone is silent all the time and unable to produce sound at all. While most people these days use their smartphones for functions that do not require sound, a completely silent phone would not fit the traditional definition of a "phone". This feature is labelled at the location where a headphone socket would traditionally be, although some recent phones have discarded the traditional headphone jack in place of wireless headphones.

; Quad camera takes four copies of every picture

: Recent phones have added up to three rear-facing cameras, offering different fields of view, monochrome cameras for low light, and a wider base for emulating depth of field effects. This phone's cameras might take four ''identical'' pictures simultaneously, which would use up storage space at 4 times the rate of a standard camera while providing no advantage.

; Front-facing camera obscura

: A {{w|camera obscura}} is a dark room or box with a small hole allowing light to enter. The size of the hole causes light travelling in straight lines to project a dim inverted image on the back of the room or box; the concept is the predecessor to a modern camera, which uses a lens to allow more light to enter. A camera obscura is not strictly speaking a camera as in an image capture device (although there are pin-hole cameras which use the same mechanism). Actual phones have front-facing conventional cameras, allowing selfies, video calling, etc.

; 3D facial contour analysis shows you a realistic preview of your death mask

: Recent computational photography effects implemented on mobile phones support facial analysis, allowing for artificial relighting or the creation of avatars. However, since a {{w|death mask}} is created to look just like the deceased's face, all cameras provide this "feature" automatically.

; Sponsored pixels

: Presumably this means that parts of the screen (pixels) can be bought in a sponsoring deal. If enough pixels are sold, your screen would be rendered unusable. It is common for advertisers to buy part of the screen real-estate on a service web site (in fact, {{w|The Million Dollar Homepage}} hosted nothing but a 1000x1000 pixel grid of advertisements), and "images" the size of individual pixels can be used to track site access without being intrusive to the user. For the xkcd Phone 2000, it appears that advertisers have access to part of the screen (worryingly, right in the middle). Slightly less intrusive approaches have been used in bookstores selling customized versions of the Kindle, for example, and it is common for cell phone networks to insist on network-specific software to be installed on a phone.

; Front and rear pop-out grips

: There are accessories that stick to the rear of a phone and can be "popped out", offering a grip, a stand, or somewhere to store headphone cables. Integrating such a feature into the phone design is novel, although some phones have incorporated kick stands. Pop-out grips are normally placed on the back of the phone to make it easier to hold with one hand. Having a second grip to the front of the phone does nothing except block part of the screen. There could be a small screen on the top of the grip since the grip is shown to contain "Sponsored Pixels".

; Humidity-controlled crisper

: A crisper is a drawer in a refrigerator meant to control the humidity to keep vegetables from drying out and getting limp. A smartphone would have no need for a crisper{{Citation needed}}.

; Antikythera mechanism

: The {{w|antikythera mechanism}} is an ancient Greek clockwork device for predicting astronomical positions. It is one of the earliest known analogue computers. While impressive for its time, by now it is obsolete by millennia.

; New York Times partnership<nowiki>:</nowiki> all photos taken with camera app are captioned in real time by reporter Maggie Haberman

: Modern phones can use machine learning techniques (usually in the cloud) to identify and tag camera content - this makes it possible to search, for example, for photos containing a particular person or subject without requiring user input. Cellphone photos are often used in contributions to social media with some form of user-provided caption. This phone appears to combine the two, using {{w|Maggie Haberman}} to provide automatic captions for photos taken by the phone's owner (although whether this is explicitly for social media use or internal to the phone is unclear).

; Spit valve

: A water key, or "spit valve," is a feature on most brass and some woodwind instruments used to empty the instrument of condensation caused by the musician's breath (and not, as is commonly thought, saliva). Of course, one wouldn't think condensation would form on the inside of a smartphone{{Citation needed}}.

; Standard USB connector

: The phone has a USB A port, but a "standard" USB connector, according to the USB standard, would be a USB B port as a phone typically acts as the "slave" device, rather than the "host" as a USB A port would imply. However, in recent updates to the USB standard, bicommunication between 2 A ports is supported.

; Coin purse-style squeeze access

: Presumably, the casing is flexible in this region, and when squeezed at the sides (a bad idea, considering the next design item) reveals the USB A port and spit valve.

; Hollow-ground

: A {{w|Grind#Typical_grinds|hollow grind}} is a type of knife (or similar sharp tool) edge noted for sharpness and general fragility, often seen in razors. This seems to imply that the phone is exceedingly smooth, which would make it difficult to hold{{Citation needed}}. This is a far more reasonable feature to apply to the included knife than the entire case.

; Absorbent

: Many modern phones are designed to be waterproof, to avoid accidents and allow use in the rain. It's also common to have some form of oleophobic coating on the screen to reduce smearing as fingers are used on the touchscreen. This phone seems to have the reverse feature and be explicitly designed to absorb things (presumably liquids--perhaps that's why it needs a spit valve). "Absorbent" is more commonly a property touted by the packaging of paper towels.

; Keyboard supports dynamic typing

: {{w|Type_system#Dynamic_type_checking_and_runtime_type_information|Dynamic typing}} is a computer programming concept and has nothing to do with typing on a keyboard.

; Backflow preventer

: A {{w|backflow prevention device}} is a mechanism that avoids the possibility of liquid (usually water) traveling in the opposite direction from the normal intent if the expected pressure is inverted. Since there is not normally any liquid flowing through a phone (unless in this case relating to the spit valve), this would not normally be a useful feature. However, some smart phones do contain pressure measuring devices such as barometers (which can also be used in some cases to detect the phone being squeezed), so maybe this phone is intended to be resilient to such conditions.

; Swiss Army partnership<nowiki>:</nowiki> folding knife (unlocks only if Switzerland is invaded)

: A {{w|Swiss Army knife}} is a folding knife, traditionally with many secondary "blades" for multiple uses such as can openers and files. Usually it is a generic term for that style of knife, but the knife in this phone surprisingly really has a connection with the army of {{w|Switzerland}}. Switzerland is known for remaining neutral (and not being invaded) in both of the World Wars of the 20th century despite war raging across surrounding countries, suggesting that it is unlikely that the knife would ever be unlocked. While such a feature on a phone (or phone case) may be useful, it is likely to be a safety concern, and a threat to convenience when security checkpoints such as airports start confiscating the phone when they notice it conceals a knife blade. What's more, a phone does not provide the ideal grip for a knife blade - especially if force is to be applied to it. This may also reference the Swiss military practice of soldiers keeping military rifles in their private homes but only being given ammunition in the event the army is mobilized.

; 100% BPA-free PCB construction

: {{w|Bisphenol A}} (BPA) is a chemical used in plastics such as waterbottles. Recent studies show that BPA can leach estrogen-like compounds into liquids, so BPA-free water bottles have become popular. PCB probably refers to a {{w|printed circuit board}}, which is made of resin-bonded fiberglass, not plastic, and which contains the electrical components that control most modern electronic devices such as phones. It may also refer to {{w|Polychlorinated biphenyl}} (PCBs), a category of persistent organic pollutants which are not used very much anymore; it would be far worse than BPA for anyone concerned with the issue.

; AMOLCD display (7-segment)

: {{w|AMOLED}} is a display technology often used in cell phones, providing thin and emissive displays. {{w|Liquid-crystal_display|LCD}} is another display technology used in phones and works by blocking light from a separate backlight. A {{w|Seven-segment_display|7-segment display}} is a device made of seven independently controlled segments (usually either LCD or LED) which can be used to display a single digit. As such, the technology is common in traditional digital watches. In contrast most phone displays are made of a uniform high-resolution pixel grid that allows arbitrary content, like random images, to be displayed, although some very old (pre-smart) cellphones and land lines did use this technology in displaying a phone number, like the {{w|Motorola Fone|MotoFone F3}}. The technology cannot represent the entire alphabet without modification (one method is to put X's on both the top and bottom squares), so it is inappropriate for displaying plain text, let alone graphics and images.

; Runs on battery for the first 6 hours, then uses gasoline

: A nod to the increased popularity of gas-electric hybrid vehicles. This would be a fantastic breakthrough for fuel cells. There have been many attempts to create a highly portable fuel cell that can be used to power phones. Although having to use gasoline instead of a USB cord would likely cause more problems for the average consumer, like the phone blowing up, a fuel cell does have some notable advantages over a standard lithium-ion battery. When comparing a fuel cell to a battery of equal size the fuel cell will be capable of powering an object for far longer than the battery. This includes lithium-ion batteries which are commonly used for powering phones and are typically the majority of its mass. This would mean one could shrink the size of the battery substantially yet still be able to provide the same amount of power. The smaller battery can be kept as is in order to reduce the weight of the phone or can free up space for more features to be installed into the phone. This might simply be the first xkcd phone that mentions that it does this. Provides a possible explanation to how the manufacturer of the phone is capable of fitting so many unusual features into the phone to begin with. Another advantage of a fuel cell powered phone is that it is independent from a working power grid (useful for disaster situations where thousands of people would no longer be capable of staying in contact with others or people who are stranded and alone) and there is no need for a bulky generator to convert the gasoline into electricity first. This is not the first time Randall has talked about this before, with much of the information here coming from what-if #128: {{what if|128|Zippo Phone}}.

; Sharpie® dual stylus (dry-erase + permanent)

: [http://en.wikipedia.org/wiki/Sharpie Sharpie®] is a brand most associated with a line of permanent fine-tip markers. While a stylus is generally a pen-like object that doesn't create markings, but instead allows finer input on a touch screen, "Dry-Erase + Permanent" implies that these are in fact markers. These would allow the user to write on the screen, but as this wouldn't allow any form on input to the phone, it would only serve as a very expensive pseudo-whiteboard. Even if they were actually styluses, having two would be of little use. Note that permanent was previously spelled "permenant", incorrectly. This was later corrected; See [[#Trivia]]

; Mouse cursor

: A feature of BlackBerry smartphones using mice has gone out of favor due to the popularity of touch screens, which are lighter and more convenient. However, Android devices, at least, still support Bluetooth HID access, and on most devices, it is possible to pair the device with a mouse (and keyboard) and access the screen through a mouse pointer. These peripherals may also be attached with {{w|USB On-The-Go}}. This can be particularly useful if the device is exporting its display to a large external screen - and {{w|Samsung_DeX|some manufacturers}} have provided tethering systems based around pairing a phone with a mouse.

The title text refers to {{w|Retina Display}}, a term used to describe Apple products with higher pixel densities. The xkcd Phone marketing team would be unable to use the term due to Apple's having registered it as a trademark, as it would likely be trademark infringement. Additionally, the {{w|Fovea centralis|central fovea region}} is a portion of your eye's retina containing the most densely packed photosensitive neurons (confusing the biological retina with the electronics display of the same name). {{w|Foveated rendering}} is a genuine computer graphics technique intended to increase performance by rendering with higher quality to the regions of the display where the user is looking, and lower quality at the edges of vision; it is expected to be useful for virtual reality (one of the uses for cell phones) as a way to deal with the required high pixel densities while managing power consumption. There are displays with variable density, in specialist uses, but such a feature is not practical in a phone because the whole area of the display is typically useful and needs to provide high resolution (as the user's eye moves across it). Also, hundreds of pixels per inch is not considered a very high resolution, as a full-HD smartphone [https://www.lifewire.com/how-many-pixels-in-an-inch-4125185 has 440.58 pixels per inch].

==Transcript==
:[The comic depicts a smartphone showing many uncommon features. The front view shows a mouse cursor and a circle in the middle. The side view reveals the circle as something like an old photo lens from 1900 extending far above the surface and four large buttons (camera lenses) at the rear. The third view is from the top and just mentions a "hollow ground." The bottom view looks like as it was opened by a can opener and shows a big USB connector and on the right a small black connection.]
:Dockless
:Silent
:Quad camera takes four copies of every picture
:Front-facing camera obscura
:3D facial contour analysis shows you a realistic preview of your death mask
:Sponsored pixels
:Front and rear pop-out grips
:Humidity-controlled crisper
:Antikythera mechanism
:New York Times partnership: all photos taken with camera app are captioned in real time by reporter Maggie Haberman
:Spit valve
:Standard USB connector
:Coin purse-style squeeze access
:Hollow-ground
:Absorbent
:Keyboard supports dynamic typing
:Backflow preventer
:Swiss Army partnership: folding knife (unlocks only if Switzerland is invaded)
:100% BPA-free PCB construction
:AMOLCD display (7-segment)
:Runs on battery for the first 6 hours, then uses gasoline
:Sharpie® dual stylus (dry-erase + permanent)
:Mouse cursor

:Introducing
:'''<big>The xkcd Phone 2000</big>'''
:We're still hoping this sounds like a futuristic number®®™®©™®

==Trivia==
The stylus was previously called 'permenant'. This was later corrected, to permanent. You can still see the original image [http://www.explainxkcd.com/wiki/images/archive/b/b4/20180531174214%21xkcd_phone_2000.png here]

{{comic discussion}}

[[Category:xkcd Phones]]
[[Category:Comics sharing name|xkcd Phones]]

Talk:1302: Year in Review

2023-11-22T14:31:35Z

Plushiefan4111:

The eclipse happened according to schedule.

"...she never saw an aurora borealis '''(or australis)'''"
Australis?
She specifically states ''northern'' lights. {{unsigned ip|141.101.81.8}}
: True, but first she says that she never say an aurora, period; so I think that we can assume that she never saw the southern lights either. —[[User:TobyBartels|TobyBartels]] ([[User talk:TobyBartels|talk]]) 19:22, 11 December 2013 (UTC)
:: She should have played Half-Life 3 ... oh, wait ...{{unsigned ip|162.158.85.69}}

Eclipses are so predictable I suspect that the 2017 eclipse was already predicted by Chinese before christ. I mean, they executed two astrologers in 2134 BCE for failing to predict one, so I'm sure others worked hard to save themselves. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 10:22, 11 December 2013 (UTC)

I think the joke of the comic is that she's giving an actual review/critique of the astronomical year itself, like one would review a movie. This is in contrast to the expected summary or recap of events occuring during the year. [[Special:Contributions/173.245.55.217|173.245.55.217]] 13:17, 11 December 2013 (UTC)Pat
: Good point; you should add that. —[[User:TobyBartels|TobyBartels]] ([[User talk:TobyBartels|talk]]) 19:22, 11 December 2013 (UTC)
::I added it now... --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 19:55, 29 June 2016 (UTC)

Coincidence that this was released the same day as [http://www.youtube.com/watch?v=H7jtC8vjXw8 rewind YouTube style 2013?]--[[User:Mralext20|Mralext20]] ([[User talk:Mralext20|talk]]) 16:31, 11 December 2013 (UTC)

I think that another subtler point this comic raises is the idea of how ridiculous it is to critique "the year" in the first place. The idea of Megan giving the year a grade highlights this, because why would you grade an arbitrary designation of time that has no agency or animacy in the first place? The title text pokes further fun at this by implying that the people behind the "Year in Review" have the power to cancel the solar eclipse, as if the news station suddenly not only has the power to pass judgement on an entire year, but they can also take away a freaking eclipse if they feel like it. Worth mentioning? --[[User:Mynotoar|Mynotoar]] ([[User talk:Mynotoar|talk]]) 07:17, 12 December 2013 (UTC)
:I don't think that it's the news station that can cancel the eclipse, but a different "they" (presumably the same ones that destroyed the comet). —[[User:TobyBartels|TobyBartels]] ([[User talk:TobyBartels|talk]]) 10:31, 12 December 2013 (UTC)
::I mentioned these "they" that can stop eclipses and destroy comets etc. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 19:55, 29 June 2016 (UTC)

Interesting to note she sat inside working on a computer during aurora back in april of 2012 in 1037[http://www.explainxkcd.com/wiki/index.php/1037#Explanation] --[[User:Calvsie|Calvsie]] ([[User talk:Calvsie|talk]]) 16:22, 12 December 2013 (UTC)

Is it a coincidence that the comic number can be rearranged to form "2013"? {{unsigned ip|108.162.208.192}}
:I was thinking the same. I'm not sure it is important though, but say he had this comic ready in good time planning to release it before new year, then Randall might have chosen this comic number for that reason... --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 19:29, 29 June 2016 (UTC)
::it might not be a coincidence. remember [[1000]] and [[2000]]? [[User:Plushiefan4111|plushie fan]] ([[User talk:Plushiefan4111|talk]]) 14:31, 22 November 2023 (UTC)

Talk:601: Game Theory

2023-11-22T14:24:31Z

Plushiefan4111:

WarGames is also referenced in the title text for http://xkcd.com/696 {{unsigned|‎Blagae}}

Even lifelong marriages usually end in one spouse surviving the death of the other spouse which is often not a happy ending. The idea in the explanation "which initially could be expected to end happily for everyone involved" is based on the shortsightedness of the sophomoric. [[Special:Contributions/162.158.122.120|162.158.122.120]] 17:51, 11 December 2019 (UTC)

game theory is also the name of a youtuber [[User:Plushiefan4111|plushie fan]] ([[User talk:Plushiefan4111|talk]]) 02:34, 22 November 2023 (UTC)
:And? There are lots{{Citation needed}} of youtubers, each with a name. Are you implying a direct causation of some kind? Of which manner? [[Special:Contributions/172.71.122.124|172.71.122.124]] 10:27, 22 November 2023 (UTC)
::well, game theory is a pretty popular youtuber! and it started 2 months after this comic was released, so im actually implying a causation in a way you probably weren't thinking of. [[User:Plushiefan4111|plushie fan]] ([[User talk:Plushiefan4111|talk]]) 14:24, 22 November 2023 (UTC)

Talk:601: Game Theory

2023-11-22T02:34:06Z

Plushiefan4111:

1037: Umwelt

2023-11-21T02:23:49Z

Plushiefan4111: i added my location because i didnt see what i should see

{{comic
| number = 1037
| date = April 1, 2012
| title = Umwelt
| image = umwelt_the_void.jpg
| titletext = Umwelt is the idea that because their senses pick up on different things, different animals in the same ecosystem actually live in very different worlds. Everything about you shapes the world you inhabit--from your ideology to your glasses prescription to your web browser.}}
{{TOC}}
*To view your personal version of the comic, visit the {{xkcd|1037|original comic}}.

==Explanation==
This was the third [[:Category:April fools' comics|April fools' comic]] released by [[Randall]]. The previous fools comic was [[880: Headache]] from Friday April 1st 2011. The next was [[1193: Externalities]] released on Monday April 1st 2013.

An {{w|Umwelt}}, as the title text explains, is the idea that one's entire way of thinking is dependent on their surroundings. Thus, this {{w|April Fools}} comic changes based on the browser, location, or referrer. Thus, what the viewer is viewing the comic on, where they live, or where they came from determines which comic they actually see. As a result, there are actually multiple comics that went up on April Fools' Day, although only one is seen.
(The term 'Umwelt,' as mentioned in the comic, refers to the semiotic theories of Jakob von Uexküll and Thomas A. Sebeok)

Information about how the wide variety of data was collected and credit for the viewers who contributed can be found [https://www.reddit.com/r/xkcd/comments/rnst4/april_fools_xkcd_changing_comic/ here].

===The Void===
[[File:umwelt the void.jpg]]

If the device or browser you are using does not support Javascript, you will simply see a static image of a white swirl on a dark background.

Possible reference to The Ring (https://imgur.com/wlGmm), as though to suggest that using an alternative browser is dismal and horrific.

Davean (xkcd's sysadmin): "[This] comic isn't available everywhere and it can come up i[n] some situation[s] only for recognized browsers."

Browser: Alternative Browser

===Aurora===
[[File:umwelt aurora.png|800px]]

One could interpret that since Megan didn't go out and therefore missed seeing the {{w|Aurora}} (northern lights), Cueball in his [[1350:_Lorenz#Knit_Cap_Girl|knit cap]] lied about it. That way, she wouldn't have felt sad that she missed out. Another interpretation could be that he decides that since she did not even bother to go outside to see such a spectacular sight he will not tell her about it. And yet another could be that he did not think it was interesting.

Cueball could possibly also be red-green colorblind, seeing the green aurorae as grey "clouds". This would serve as an example for the theme of the comic, as a non-colorblind person and a colorblind person seeing the same color would perceive it differently, one seeing it as its true color, and the other seeing it without the shade of color they cannot see. If this is the case, then it would be a reference to umwelt, as Cueball would be living in a world where the auroras do not reach his location.

In real life, [https://www.huffpost.com/entry/the-northern-lights-dont-look-anything-like-they-do-in-photos_n_5500a4d9e4b0e62d0dd4f9bb aurorae are usually seen as grey/white clouds] to the naked eye, as our eyes cannot perceive the "greener" colors as well in the dark.

This image changed based on the size of the browser window including different panels at different sizes.

Locations: Canada, Boston, Indiana, Maine, New York, Ohio, Oregon, Texas, Minnesota, Norway, Denmark, France, Ireland, Rhode Island, Mississippi, London (on Firefox). Also in Virginia, but using Ohio in the first panel; in Maryland, but using Canada in the first panel; in Marion, Illinois, but using Canada in the first panel along with the phrase "as far south as us" in the first panel, and in Utah, also using the phrase "as far south as us", same with Colombia, Spain and Georgia.

In [[1302: Year in Review]] a possibly different Megan has a completely different approach to the chance of seeing northern lights, as that was the only event she was looking forward to in 2013, and it failed. If this is the same Megan, perhaps she learned that there actually were northern lights in her area from another source, and so desperately wanted to have another chance to see them.

===Snake===
[[File:umwelt snake composite 1024.png]]
[[:File:umwelt snake composite.png|Full size]]

The joke here is the extreme length of snakes. The world's longest living snake is the {{w|reticulated python}}, the longest ever measuring over 22 feet (6.95 meters). The blue and orange circles refer to the hit game {{w|Portal}}.
There is also a reference to the book "The Little Prince" in the second panel, where there is a large bulge in the snake that looks like an elephant. The Little Prince starts out by mentioning a drawing that the author made when he was six that showed an elephant inside a snake.

Also, the number and content of the panels changes depending on the size of your browser window.

This image changed based on the size of the browser window including different panels at different sizes.

Specific AltText for this image: Umwelt is the idea that because their senses pick up on different things, different animals in the same ecosystem actually live in very different worlds. Everything about you shapes the world you inhabit -from your ideology to your glasses prescription to your browser window size.

Location: Texas (on Chrome Version 33.0.1750.154 m), New Jersey, California (on Chrome Version 39.0.2171.95), Maryland, Massachusetts (Safari for iOS, Chrome version 49.0.2623.112), Connecticut (Safari for iOS, Chrome Version 73.0.3683.103, Internet Explorer, and Microsoft Edge), Virginia (on Chrome), Michigan (Firefox v46.0.1), Penang (Chrome Version 65.0.3325.162), London (Microsoft Edge).

===Black Hat===
[[File:umwelt tortoise 1024.png]]
[[:File:umwelt tortoise.png|Full size]]

Cueball as an analyst attempts to psychoanalyze [[Black Hat|Black Hat's]] [[72: Classhole|classhole]] tendencies. Cueball's quote and the whole setup is a direct reference to the movie {{w|Blade Runner}} (1982) and Black Hat is taking the Voight-Kampff test which is used to identify replicants from real humans.

Black Hat's reason for not helping the tortoise is that ''it '''knows''' what it did'' and thus in Black Hat's world view it deserves being turned over. The final part of the joke is that when zooming out it turns out that there is a tortoise behind Black Hat and he has actually already turned it over for what it did.

Location: Seems to appear mostly in "other countries" — those without location-specific comics.

===Too Quiet===
[[File:umwelt too quiet 1024.png]]
[[:File:umwelt too quiet.png|Full size]]

A reference to {{w|Jurassic Park (film)|Jurassic Park}} which has been [[87: Velociraptors|constantly]] [[135: Substitute|referred]] [[1110: Click and Drag|to]] [[155: Search History|before]] [[758: Raptor Fences|in]] this comic.

Also referencing the film {{w|2 Fast 2 Furious|2 Fast 2 Furious}}, an entertaining, yet intellectually unprovoking sequel in a popular film franchise, which is aimed at teenagers and young adults, prompting the blunt response from the stickman. The fact that Steve would use such a cliché {{w|2000s (decade)|noughties}} movie term in such an intense moment, and the subsequent curse, is the joke in this comic.

Location: short version — iPhone 5c Safari browser in Texas, iPhone 5 Chrome Browser in Minnesota, long version - Google Chrome browser in Indiana, Windows 8 Laptop

===Pond===
[[File:umwelt pond mobile.png]][[File:umwelt pond wide.png]]

Two different versions showed, the narrower version for mobile devices.

Location: The Netherlands and various other countries.

===Galaxies===
[[File:umwelt galaxies 1024.jpg]]
[[:File:umwelt galaxies.jpg|Full size]]

Megan is distracted from her conversation with [[Cueball]] by realizing that the space behind his head, from her vantage point, contains millions of galaxies. This is similar to an [https://nssdc.gsfc.nasa.gov/image/astro/hst_deep_field.jpg incredible photograph] taken by the Hubble Telescope, in which a tiny dark area of space in fact contained numerous galaxies.

The title text is an imaginative leap from this scenario: that the galaxies would be up to no good once Cueball is turned away from them. This is presumably a reference to [https://www.mariowiki.com/boo Boo], an enemy from certain Mario games who moves toward Mario only when Mario is facing away from Boo.

This comic was only reported once... the intended environmental context is a mystery.

Location: unknown

===xkcd Gold===
[[File:umwelt xkcd gold.png]]

This is probably a reference to the 4chan Gold Account, an implementation on 4chan that does not actually exist, and is usually used to trick newcomers into revealing their credit card numbers. The joke is that "Gold Account" users can supposedly block other users from viewing images they have posted. The fifth panel is probably a reference to Beecock, a notorious set of shocker images. 4chan's moderators have been known to give out "beecock bans" or "/z/ bans" to particularly annoying users, which redirect the user to a page containing beecock and the text "OH NO THE BOARD IS GONE".

Referrer: 4chan

===Yo Mama===
[[File:umwelt dog ballast.png]]

Possible reference to Kurt Vonnegut Jr.'s "{{w|Harrison Bergeron}}."

The joke is that people's different experiences shape how they perceive the world in that the people who live in this world would perceive the joke as funny, while people in our world would not get it. This is the idea of umwelt mentioned at the top of the context where different individuals perceive the world differently.

Refer: Facebook

===Reddit===
[[File:umwelt reddit.png]]

Reference to referencing, because Reddit, as a referring site, likes references to its referencing in its references.

This comic also features recursive imagery similar to [[688: Self-Description]] where the second panel embeds the entire comic within itself. (Except, conspicuously, the arrow indicating that it is "You" in the first panel.)

One of the browser tabs visible in the center panel is {{w|Elk}} on Wikipedia.

Referrer: Reddit

===Buns and Hot dogs===
[[File:umwelt somethingawful.jpg]]

This is a reference to the question "Why do hot dogs come in packages of 6 while buns come in packages of 8?"

Another, more sexual reference to this question can be found in [[1641: Hot Dogs]].

Referrer: SomethingAwful, Questionable Content, & MetaFilter

===Twitter===
[[File:umwelt twitter.jpg]]

A summary of the "content" typically found on Twitter.

In the tweet feed, there are three tweets about some podcast on the top, followed by the tweet containing link they clicked on to get to the comic, tweets about Rob Delaney, unspecified passive-aggressive tweets, and a tweet from {{w|Horse_ebooks}} retweeted by one of the users the reader follows.

On the left, the topmost dialog, with profile information, shows that the user has posted 1,302 tweets, but only follows 171 people and has even fewer followers, at a measly 48. This is marked with a sad face, implying that the user wants more followers.

Below that is the "who to follow" dialog, which is written up as consisting of "assholes".

Below that is the "trending tags" dialog for the United States. It is full of tags about word games, tags about misogyny, and tags about Justin Bieber.

Below that is an unidentified dialog full of "stuff your eyes automatically ignore". And finally, on the bottom is the background color, which is "a really pleasant blue".

Referrer: Twitter

===Wikipedia===
[[File:umwelt wikipedia wide.jpg]]
[[File:umwelt wikipedia mobile.png]]

The term {{w|Mile High Club}} (or MHC) is a slang term applied collectively to individuals who have had sexual intercourse while on board an aircraft. Randall says that reading the news articles on it has distracted him from making that comic.

Two different versions shown, the narrower version (the single panel with all the text) for mobile devices.

Referrer: Wikipedia

===Google Chrome===
[[File:umwelt chrome1.jpg]]

{{w|Sergey Brin}} (born August 21, 1973) is an American computer scientist and Internet entrepreneur who, with Larry Page, co-founded Google, one of the most profitable Internet companies. As of 2013, his personal wealth was estimated to be $24.4 billion. Randall makes the joke that as the founder of Google, Brin's permission would be needed to use Google Chrome. Because there are millions of people who use Google, it is likely that at least some of the time Brin would be asleep, thus he would need to be woken.

Browser: Chrome

===Chrome/Firefox===
[[File:umwelt chrome2.png]]

Mozilla {{w|Firefox}} is a free and open-source web browser developed for Windows, OS X, and Linux, with a mobile version for Android and iOS, by the Mozilla Foundation and its subsidiary, the Mozilla Corporation. Cueball is complaining about {{w|Google Chrome}}, to which [[Ponytail]] replies that there is an {{w|add-on}} that fixes what he is complaining about. When questioned, she replies that the add-on is Firefox, which isn't an add-on at all and is instead a different browser.

Browser: Chrome

===Google Chrome-2===
[[File:umwelt chrome3.png]]

This panel references Google Chrome's error screen, which shows a puzzle piece. The comic humorously implies that Chrome is looking for that piece. When completing jigsaw puzzles, a common strategy is to figure out where the pieces must be from their geometry rather than from the picture they create. In this case, the text suggests that Chrome believes the puzzle piece connects to the pieces which form one of the corners of the puzzle, which may seem impossible because any piece that links up to a corner would usually have at least one flat edge, which this piece has none. However, more complicated puzzles have complex shapes and are not always simply approximate squares with tabs and blanks.

Browser: Chrome or silk on desktop view

===Mozilla Firefox Private Browsing===
[[File:umwelt firefox incognito.png]]

Another reference to crashing web browsers.
Firefox shows the history when it crashes.
Browser: Firefox (Incognito only?)

===Internet Explorer===
[[File:umwelt ie.png]]

Yet another reference to crashing web browsers

Browser: Internet Explorer

===Maxthon===
[[File:umwelt maxthon.png]]

Browser: Maxthon

===Netscape Navigator===
[[File:umwelt netscape womanoctopus.png]]

[[File:umwelt netscape man.png]]

{{w|Netscape Navigator}} was a web browser popular in the 1990s.

Browser: Netscape

===Rockmelt===
[[File:umwelt rockmelt.png]]

{{w|Rockmelt}} is a social-media-based browser.

Reference to the gospel song {{w|Longing for Old Virginia: Their Complete Victor Recordings (1934)|"There's no hiding place down here" by The Carter Family}}, later covered by Stephen Stills.

:I run to the rock just to hide my face
:And the rocks cried out, no hiding place
:There's no hiding place down here

It may additionally be a reference to the ''Babylon 5'' episode "And the Rock Cried Out, No Hiding Place," which featured the song.

Browser: Rockmelt

===Plugin Disabled===
[[File:umwelt plugin disabled.png]]

When the Google Chrome web browser does not have the required software (called a plug-in) to display a web page's content, it displays a puzzle piece icon and an error message. In this case, Chrome informs the user that the content is impossible to display.

Browser: Plugin (?) Disabled, Safari Desktop

===Corporate Networks===
[[File:umwelt corporate general.png]]
[[File:umwelt corporate amazon chrome.png]]
[[File:umwelt corporate amazon firefox.png]]
[[File:umwelt corporate amazon other.png]]
[[File:umwelt corporate google chrome.png]]
[[File:umwelt corporate microsoft chrome.png]]
[[File:umwelt corporate microsoft firefox.png]]
[[File:umwelt corporate microsoft other.png]]
[[File:umwelt corporate nytimes chrome.png]]
[[File:umwelt corporate nytimes other.png]]

These error messages appear if the user is on a network owned by one of the corporations noted. The error message includes a warning against speaking on the company's behalf.

ISP: Corporate networks of Amazon, Google, Microsoft, NY Times

===Military===
[[File:umwelt military.png]]

[[Cueball]] assumes that anyone using a military network has an important job like watching for incoming missiles. He includes a thank-you to the user for their military service.

ISP: Military networks

===T-Mobile===
[[File:umwelt tmobile.png]]

Reference to T-Mobile's distinguishing feature (at the time it was written) of weaker coverage, in relation to other major providers.

ISP: T-Mobile

===Verizon and AT&T===
[[File:umwelt verizon.png]]

[[File:umwelt att.png]]

Reference to Verizon and AT&T's scandals/controversy regarding implementation of bandwidth caps.

ISP: Verizon and AT&T

===France===
[[File:umwelt france.jpg]]

A common joke about France is that the nation does not win wars. This originated from France's annexation by Germany during World War II, and America's late entry into the war, which is sometimes portrayed humorously as a case of America 'saving' Europe, in this joke particularly France (the role of the French resistance is usually not mentioned), leading to a common American joke at the expense of France's military prowess [https://www.albinoblacksheep.com/text/victories.html][https://politicalhumor.about.com/library/images/blpic-frenchmilitaryvictories.htm][https://politicalhumor.about.com/library/jokes/bljokefrenchmilitaryhistory.htm]. When France did not form part of the coalition that invaded Iraq in 2003, aligning with the many countries that condemned U.S. action, the joke was revived.

A Google search of "French Military Victories" + 'I'm feeling lucky' used to direct to "did you mean: french military defeats" (due to a {{w|Google bomb}}). Cueball is trying to show this to his friend, who is French. However, his joke backfires, as his friend immediately points out that the stereotype of France not having military victories is undercut by the fact that one of the most innovative military commanders in history, Napoleon, was French by citizenship (though Italian/Corsican by culture, as the French annexed Corsica a few months before his birth to an Italian noble family), and in fact conquered much of Europe.

Following the theme of umwelt, the comic highlights the two characters' differing perspectives: The American thinks that France is a military failure, while the Frenchman thinks of Napoleon.

The last line of the comic further implies that Cueball is not as smart as he thinks he is in regards to anything French, as he mispronounces the French loan word "{{w|Touché (fencing)|touché}}".

Locations: France & Quebec

===Germany===
[[File:umwelt germany.png]]

This comic references the {{w|Berlin airlift#The start of the Berlin Airlift|Berlin Airlift}}, a relief measure for citizens in West Berlin (surrounded by East Germany) instituted by the Western Allies after World War II. In reality, the Western Allies flew a grand total of 500,000 tons of food over the Soviet blockade in planes. Randall puts a twist on this event by making it more fun: dropping supplies from a grand chairlift. The play on words is that "chairlift" rhymes with "airlift" and thus makes an easy substitution. The chair force is also a name that other service branches use to make fun of the air force.

Location: Germany

===Israel===
[[File:umwelt israel.png]]

Translation: Mom, I met a great guy! But he's not Jewish. ...Wait, what do you mean "neither are we"? I'm completely confused.

A reference to the multiple use of the word Jewish to denote both a {{w|Judaism|religious group}} and a {{w|Jews|nationality/ethnicity}}, as well as the stereotype of Jews holding low opinions of interfaith marriage.

A side note: Randall accidentally drew an apostrophe instead of the similar-looking Hebrew letter י everywhere that letter should appear.

Location: Israel

===Carnot Cycle===
[[File:umwelt japan.png]]

A pun on "cycle"; a "{{w|Carnot cycle}}" is a thermodynamic cycle (e.g. refrigeration). Its efficiency depends on the temperature of the hot and cold 'reservoirs' in which it is operating. The icon on the side of the motorcycle resembles a [https://upload.wikimedia.org/wikipedia/commons/thumb/0/06/Carnot_cycle_p-V_diagram.svg/1000px-Carnot_cycle_p-V_diagram.svg.png graph of the Carnot cycle.]

Location: Japan

===UK===
[[File:umwelt uk.jpg]]

He worded this as though to imply that the UK is a state of the U.S., and an unimportant one at that, which pokes fun at the UK, creating a paradox (sort of).

Location: UK

===Blizzard===
[[File:umwelt disasters blizzard.png]]

This comic is aimed at the debate over whether earthquakes or blizzards are harsher conditions to live under. In keeping with the theme of umwelt, the comic demonstrates that the two people perceive the world in two different ways due to their different experiences: The Californian perceives a mild earthquake and a severe blizzard, while the Northeasterner perceives a severe earthquake and a mild blizzard.

For each location this displayed in, the state name was substituted in the third panel.

Locations: Alabama, Boston, Chicago, Dallas, Georgia, Halifax, Illinois, Michigan, Minnesota, Missouri, the Northeast, Ohio, Oklahoma, Ottawa, Pennsylvania, Philadelphia, Texas, Toronto, Tennessee, New York, Wisconsin

===Tornado===
[[File:umwelt disasters tornado.png]]

This comic is aimed at the debate over whether earthquakes or tornadoes are harsher conditions to live under. In keeping with the theme of umwelt, the comic demonstrates that the two people perceive the world in two different ways due to their different experiences: The California perceives a mild earthquake and a severe tornado, while the Midwesterner perceives a severe earthquake and a mild tornado. It's similar to [[#Blizzard|Blizzard]].

For each location this displayed in the state name was substituted in the third panel.

Locations: Alabama, Dallas, Illinois, Georgia, The Midwest, Missouri, Ohio, Oklahoma, Ottawa, Tennessee, Texas (and Virginia, but it used Ohio in the third panel)

Tornadoes are a [[:Category:Tornadoes|recurring subject]] on xkcd. The picture used in [[1754: Tornado Safety Tips]] very reminiscent of the one from this version of Umwelt. [[Category:Tornadoes]]

===Hurricane===
[[File:umwelt disasters hurricane.png]]

This comic is aimed at the debate over whether earthquakes or hurricanes are harsher conditions to live under. In keeping with the theme of umwelt, the comic demonstrates that the two people perceive the world in two different ways due to their different experiences: The Californian perceives a mild earthquake and a severe hurricane, while the Easterner perceives a severe earthquake and a mild hurricane. It's similar to [[#Blizzard|Blizzard]] and [[#Tornado|Tornado]].

For each location this displayed in the state name was substituted in the third panel.

Locations: D.C, Florida, Georgia, Houston, Miami, New Jersey, North Carolina, South Carolina, Virginia

===Lake Diver Killer===
[[File:umwelt lake diver.png]]

This comic shows a news reporter standing in front of a lake. She is reporting on a serial killer who targets divers. As more divers are sent in to investigate and/or search for bodies, more divers go missing, the implication being that they were also murdered. The more likely reason is the lake itself is dangerous for diving, and the divers probably drowned from natural hazards (undercurrents, entanglement, running out of oxygen in tanks, etc.) instead of a malicious assailant. Also, this is a sort of loop, where each time a diver gets killed, the investigative team goes and investigates, causing more divers to get killed, causing more deaths, and so on.

Location: Bay Areas, Metro Detroit, Vermont showed an image specifically referencing Lake Champlain

===Lincoln Memorial===
[[File:umwelt lincoln memorial.png]]

{{w|Abraham Lincoln}}, the 16th president of the United States of America, was not an entity composed wholly of nanobots that attempted to consume the entire nation to then be imprisoned within the {{w|Lincoln Memorial}}.{{Citation needed}} The inscription references the epitaph at the actual Lincoln Memorial, which reads "In this temple, as in the hearts of the people for whom he saved the union, the memory of Abraham Lincoln is enshrined forever".

Locations: Illinois & Washington, D.C.

===Helicopter Hunting===
[[File:umwelt helicoptor.png]]

In Alaska, governments and individuals have {{w|Wolf hunting#North America 2|shot wolves en masse from helicopters}} in an attempt to artificially inflate populations of game, such as moose and caribou, to make hunting them easier. This is opposed by many, as the game populations are not endangered (thus, this threatens ecological balance); wolves are a small threat to livestock in North America; most of the wolf body —including meat and bones— goes wasted as they are sought mainly for their pelts.

Location: Alaska

===Newspaper===
[[File:umwelt life scientists.png]][[File:umwelt life rit.png]][[File:umwelt life umass.png]]

Creating new life has long been a well understood process, in a lab or otherwise.

This comic is likely a reference to the title text of [[983: Privacy]]

Location: Various

Specific versions appeared for RIT and UMass Amherst

===Robot Paul Revere===
[[File:umwelt paul revere.png]]

Combination of the legend of {{w|Paul Revere#"Midnight Ride"|Paul Revere}} and a computer bit that differentiates between two situations by indicating a zero or a one.

Location: Boston

===Counting Cards===

All four colleges in this series are in Massachusetts and, being similar, in pairs, rival each other to some extent (Harvard-MIT, and Smith-Wellesley). The comic contains a reference to the {{w|MIT Blackjack Team}}, which entered popular culture via the {{w|21 (2008 film)|film 21}}, and a possible reference to Orwell's book '1984' and/or {{w|Chain of Command (Star Trek: The Next Generation)|popular homage to it via Star Trek}}: "There are four lights."[https://www.youtube.com/watch?v=ChYIm6MW39k]

Bonus: The thought-gears in panel 3 are spinning against each other.

Location: Harvard

[[File:umwelt counting cards harvard.png]]

Location: MIT

[[File:umwelt counting cards mit.png]]

"Course 15s" at MIT are the business major students, often mocked for taking a less-rigorous program. The different interpretation for why the MIT students could not count cards compared to Harvard may be a reference to the theme of umwelt.

Location: Smith

[[File:umwelt counting cards smith.png]]

Location: Wellesley

[[File:umwelt counting cards wellesley.png]]

Both Wellesley and Smith are all-women colleges in Massachusetts.

===Giant Box Trap===
[[File:umwelt box trap.png]]

Randall got his undergrad in Physics at the {{w|Christopher Newport University}}, and was scheduled to return shortly to give a talk. The "Trible" figure on the right is Paul Trible, the then-president of CNU. This comic depicts a classic trap, where an upside-down box is propped up with a stick. When the stick is removed, by pulling a string, the box falls and traps whatever is underneath it. Aside from the joke of the obvious trap, there's also the fact that the president would not be responsible for revoking unearned diplomas.

Location: Christopher Newport University

===Chemo Support===
[[File:umwelt chemo.jpg]]

[[Cueball]] has shaved his head in support of people going through {{w|chemotherapy}} but, as he is always depicted as a stick figure with no hair, no one can tell.

Randall's now-wife was diagnosed with breast cancer, and apparently DFCI is where they've been spending much of their time.

Location: Dana-Farber Cancer Institute

===Reviews===
[[File:reviews.png]]

The previous strip appears twice when using [[wikipedia:Tor (anonymity network)|Tor]].

Browser: Any using Tor, xkcd API (JSON, RSS, Atom), w3m, and reports of seeing it on a Kindle Fire HD; also happens if visiting with a browser that does not support JavaScript (such as Firefox with NoScript)

===Nothing===

[[File:Umwelt blank.jpg]]

In some cases, the comic can be completely absent, with only the top and bottom buttons visible. On most newer browsers, this is caused by a script loading part of the comic via a HTTP request while the rest of the webpage is delivered over HTTPS. This is referred to as [https://developer.mozilla.org/en-US/docs/Web/Security/Mixed_content mixed content] and is blocked on modern browsers by default due to security concerns. This version of the comic is therefore likely not an intended outcome, but rather an unintended consequence of how this comic was implemented. [https://mastodon.social/@chromakode/109531309722997557 It has been confirmed] that this was not intentional and will be fixed. Since this comic's release, all devices viewing it have returned two rows of navigation buttons if near IP address 69.114.249.104.

==Transcript==
:'''[This section only covers the first three comics. For the transcript of the entire comic, go to the [[1037: Umwelt/Transcript|full transcript page]].]'''

===The Void===
:[An epic void with a bright light shining right on you.]

===Aurora===
:[Cueball heading out past Megan comfortably sitting in front of a desk.]
:Cueball: Apparently there's a solar flare that's causing some Great Aurorae. CBC says they may even be visible here! Wanna drive out to see?
:Megan: Hockey's on.
:Cueball: Ok. Later.

:[An expansive, marvelous image of emerald green northern lights, floating down through the sky.]

:Megan: See anything?
:Cueball: No, just clouds.
:Megan: Not surprised.

===Aurora-US===
:[Cueball heading out past Megan comfortably sitting in front of a desk.]
:Cueball: Apparently there's a solar storm causing northern lights over Canada. CNN say they might even be visible {Options: "As Far South As Us", "Here in Boston", "Maine", "Ohio", "Oregon", "New York"}! Wanna drive out to see?
:Megan: It's cold out.
:Cueball: Ok. Later.

:[An expansive, marvelous image of emerald green northern lights, floating down through the sky.]

:Megan: See anything?
:Cueball: No, just clouds.
:Megan: Not surprised.

===Snake===
:[Two people standing next to each other. Megan is holding the head end of a snake. Depending on the width of your browser, the snake is: three frames, the third of which has a little bit of a bump; the first frame has a human-size bump, the second has a third person looking at the snake, and the third has the snake going though two Portals; a squirrel and the human-size bump in the first frame, a ring next to the third person in the second frame, and Beret Guy riding the snake in front of the portal; or The squirrel, a fourth person within the snake being coiled, and the human bump in the first frame, the ring, a fifth person in love, and the third person in the second frame, Beret Guy and the portal in the third frame, and the same two people in the fourth frame.]

:Megan: I found a snake, but then I forgot to stop.

:'''[For the transcript of the entire comic, go to the [[1037: Umwelt/Transcript|full transcript page]].]'''

==Trivia==
* The Reddit user [https://www.reddit.com/user/SomePostMan SomePostMan] created a [https://www.reddit.com/r/xkcd/comments/t6wmh/all_umwelt_1037_comics_in_two_imgur_albums/ post] that collected all of the Umwelt comics and added explanations. Much of his information is now included in this wiki.
* At the start of the [https://xkcd.com/1037/info.0.json official transcript of this comic], the writer added a note alluding to its extreme length:
:: <nowiki>[[Two people...]]</nowiki>
:: ((..wait.. <scrolls through a listing of everything> oh goddammit Randall. Thanks a bunch, dude. I better get a raise for typing out all this))
:: [[Two people standing next to each other.
* This comic was released on April 1 even though that was [[:Category:Sunday comics|a Sunday]] (only the third comic to be released on a Sunday). But it was only due to the April Fools' joke, as it did replace the comic that would have been scheduled for Monday, April 2nd. The next comic, [[1038: Fountain]], was first released on Wednesday, April 4th. This was the first that could be different for different readers.
* This comic displays the previous comic, Reviews (1036), when you try to view it on uni.xkcd.com.

{{comic discussion}}

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Talk:1395: Power Cord

2023-11-20T00:26:30Z

Plushiefan4111:

Is there any reason why you would have to avert your eyes... i would think that it may create a dust cloud from the keyboard... but it is a fictional situations, so there may be other reasons...[[Special:Contributions/108.162.249.218|108.162.249.218]] 06:02, 16 July 2014 (UTC)

Has anyone noticed Beret's uncanny ability with power cords? [[User:Thendenster|Thendenster]] ([[User talk:Thendenster|talk]]) 06:29, 16 July 2014 (UTC)

What a stupid unrealistic comic. Things that are blown up with air don't float! >:-C --[[Special:Contributions/108.162.254.97|108.162.254.97]] 07:26, 16 July 2014 (UTC)
:: They do if you start off underwater, or start off in your living room, and then dunk the balloon in crazy glue (to give the balloon shell some rigidity), and then take the inflated balloon underwater, or into a caisson, or a hyperbaric chamber - both 'easily' found at underwater worksites.
:: Or if you're blowing a balloon using a straw that has a one way valve, which goes from your mouth, through your space-suit, and to a balloon which is outside your spacesuit, when you're on the Venusian surface.
:: They can do so, even on Earth, if the air coming out of your mouth is filtered such that the only bits let through are the components of air that are lighter than the natural mixture of air. (For example, a power line that's been highly charged, could ionise Oxygen atoms much more preferentially than ionising Nitrogen atoms as the flow past the sharp edges of the prongs. The ionised oxygen would react with surrounding bits, and be fixed into a solid state... leaving only the Nitrogen to continue flowing). Nitrogen is lighter than Air. Do this for long enough (a big enough balloon) and it will start floating. If you want to do it faster, and with a smaller balloon - pass the exhaled air over some chemical that absorbs and reacts with carbon-di-oxide (Alkali[ne] hydroxides), absorbs and reacts with water vapour (dessicant), absorbs and reacts with oxygen (bacteria), and absorbs and reacts with nitrogen (nitrogen fixing bacteria). [[Special:Contributions/108.162.208.169|108.162.208.169]] 17:39, 20 July 2014 (UTC)

You obviously don't know how gross a keyboard can be...
Also, if you think this is unrealistic, you obviously haven't read enough XKCD. [[Special:Contributions/108.162.249.220|108.162.249.220]] 07:41, 16 July 2014 (UTC)
:Yes and as can be seen someone has already added a link to the previous comic on gross keyboards so... [[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 07:45, 16 July 2014 (UTC) And who says that it is not blown up with helium or the like. First of all we would never see if a stick character was inflated - so Beret guy could be big and filled with helium. Or it is just his crazy ability that makes his blow into the socket turn the "air" into helium in the PC - or something much lighter since the shown inflation would never be enough to carry a laptop. In the end the whole comic is just an excuse to make three crazy puns (like them or not, that is up to the reader) and refeer back to [[237]] [[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 07:45, 16 July 2014 (UTC)

:I think 108.162.254.97 is being sarcastic. Pointing out the fact that things filled with air don't float instead of the obvious impossibility of blowing air through an electric wire. [[Special:Contributions/108.162.216.88|108.162.216.88]] 14:46, 16 July 2014 (UTC)BK

:An object filled with air wont go up, but may still bounce out of hand and foat. In this case the sudden increase in volume have ejected the inflated laptop. Since an object almost-as-light-as-air is really sensitive to move of air, the laptop could (in the unlikely case of it happening) behave that way.[[Special:Contributions/141.101.70.103|141.101.70.103]] 09:11, 18 July 2014 (UTC)

Given that Beret Guy often does crazy correctitive things when he perceives something is amiss in his (surreal) visions of the world, I'm wondering if that's a specific protest against having the power chord plugged into the laptop but not the wall (during normal operation, I presume, rather than deliberately depleting the battery of testing the reduced-power settings, or temporarily while other powered devices require the power sockets with more urgency). I don't know whether I personally find this set-up more or less disturbing than a power-chord plugged into the wall but ''not'' plugged into the intended laptop. Although (apart from the risk of leaving residue across the pins), the comic's version is at least safer than the opening text of the explanation would suggest. [[Special:Contributions/141.101.99.192|141.101.99.192]] 12:11, 16 July 2014 (UTC)

...inflation in an xkcd comic? Cue the inflatophobes... [[User:Greyson|Greyson]] ([[User talk:Greyson|talk]]) 13:34, 16 July 2014 (UTC)

Beret Guy is obviously exhaling a lighter-than-air gas, either by just taking a large breath of helium beforehand or by a very special cellular breathing process. Moreover, it should be noted that one averts one's eyes before something holy. [[Special:Contributions/108.162.220.41|108.162.220.41]] 11:02, 16 July 2014 (UTC)
:You also avert your eyes when you know something is going to be propelled at your head from a compressed air keyboard... -Pennpenn [[Special:Contributions/162.158.2.221|162.158.2.221]] 02:49, 11 June 2015 (UTC)

Transcript accuracy: is Cueball actually looking up in panel 2? He's still typing after all. (Also, [[https://www.youtube.com/watch?v=H0f0QzMNk-E&t=17 power chords?]]) --[[Special:Contributions/108.162.221.87|108.162.221.87]] 00:48, 17 July 2014 (UTC)

why are all the ips from cloudfare servers? sockpuppets?[[Special:Contributions/173.245.53.121|173.245.53.121]] 09:08, 18 July 2014 (UTC)
: explainxkcd is hosted through Cloudflare's cdn and all of us connect through Cloudflare. --[[Special:Contributions/172.68.141.146|172.68.141.146]] 17:05, 9 July 2020 (UTC)
My mother once blown a lighter than air balloon, our best guess was that it was hot air from some fever or something. [[Special:Contributions/108.162.210.233|108.162.210.233]] 19:56, 18 July 2014 (UTC)
:That would only work for as long as the air in the balloon is warmer than the air surrounding it. I doubt that the balloon is that good as an isulator to have this occur for long. --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 11:13, 16 January 2020 (UTC)

We can see his screen a bit in panel 3. Can anyone tell what he's doing? [[Special:Contributions/172.69.62.203|172.69.62.203]] 22:07, 2 September 2021 (UTC)
:Reading xkcd, it looks like. Good catch. [[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 16:25, 6 December 2021 (UTC)
::Looks more like a newsletter(/paper), to me. A traditional printed-style (but PDFed, scanned or HTML+CSSed, obviously) two-column split of various paragraphs and images (no obvious headlines). The obvious image looks less than stick-figure... could be a boxer in action, but the residual resolution (and the method of interpolation needed to 'read between the dots') leaves that a very open issue and maybe flavoured by the eye of this particular beholder, unable to unsee what the vague first imrpession was. But it looks like it was doodled as more than a stick-figure (within the limitations of the pixelation), and doesn't have that basic Comic-like look of XKCD (or even a What-If). Though maybe one of the more Infographic ones, extending well off page? [[Special:Contributions/172.70.162.147|172.70.162.147]] 21:20, 6 December 2021 (UTC)
::: i did a manual quality upscale. its at https://drive.google.com/file/d/1vznnh7ZkSJXei9brI4sNE9cVM8-QmXOc/view?usp=sharing [[User:Plushiefan4111|plushie fan]] ([[User talk:Plushiefan4111|talk]]) 00:26, 20 November 2023 (UTC)

Talk:1086: Eyelash Wish Log

2023-11-19T21:18:24Z

Plushiefan4111:

This is one of my favorite xkcd comics ever. I can't stop laughing. -- #TEBOWTIME 17:14, 17 August 2012 (UTC)
: i know right?? feb. 27th is by far the best... --[[User:Douglasadams472|Douglasadams472]] ([[User talk:Douglasadams472|talk]]) 03:12, 16 December 2012 (UTC)

: It seems to me that February 6th's wish implies that, as a result of the previous day's wish, he now has an absurdly large number of eyelashes. Opinions? --[[User:Bobidou23|Bobidou23]] ([[User talk:Bobidou23|talk]]) 02:58, 26 May 2013 (UTC)
:i thought they were absurdly long eyelashes, like his wings in infinite wings (sry cant make links) {{unsigned ip|173.245.54.5}}
::Actually, the guy with unlimited wings is Beret Guy.. (as seen in the "strange powers of beret guy" category on this site).. Black Hat's the "classhole". --[[User:JayRulesXKCD|JayRulesXKCD]] ([[User talk:JayRulesXKCD|talk]]) 11:31, 13 October 2016 (UTC)

: I thought of Black Hat having a crazy number of eyelashes, but not attached to him, so he can't pull them for a wish. They're just in a pile on the floor or something. {{unsigned ip|173.245.56.187}}

I feel that each wish should be thoroughly explained, or at least briefly mentioned. {{unsigned ip|108.162.238.193}}
: +1, Marking this 'incomplete' [[User:Spongebog|Spongebog]] ([[User talk:Spongebog|talk]]) 20:09, 7 July 2014 (UTC)

March 15 may reference a painting of M.C. Escher so named "House of Stairs" [[Special:Contributions/199.27.128.79|199.27.128.79]] 08:19, 8 March 2014 (UTC)

:"Revocation of rules" and especially "meta-wishes" must be references to [http://amberbaldet.com/uploads/little-harmonic-labrynth.html "Typeless Wish" scene in Göedel, Escher, Bach]. "banish people into the TV show they're talking about" might(?) also reference the plot there where Achiles and Tortoise enter Escher's Convex and Concave painting after discussing it. Surpsingly to me, that episode's only Escher illustrations are Concave and Convex & Reptiles; House of Stairs does not appear anywhere in the book. [[User:Cben|Cben]] ([[User talk:Cben|talk]]) 00:48, 9 September 2014 (UTC)

What did "zero wishes" mean? [[Special:Contributions/173.245.48.86|173.245.48.86]] 18:16, 2 April 2014 (UTC)
:Often when configuring software (especially regarding limits) 0 is taken to mean infinite, for example in a mail server's config file there may be an entry that looks like "Max number of connections: (enter 0 for unlimited)" [[Special:Contributions/141.101.98.170|141.101.98.170]] 19:24, 7 July 2014 (UTC)

:My take on "zero wishes", is that it is a bit of black hattery. He wants to abuse any system he finds, by asking for zero wishes he wants to cause the eyelash wish system to crash in some way. Its not an attempt to gain more wishes, its an attempt to bring the wish system down.[[Special:Contributions/141.101.98.165|141.101.98.165]] 21:16, 8 July 2014 (UTC)

My take on the title text was that Black Hat wanted to alter friction for his own amusement, rather than to affect the outcome of a sporting event as the current explanation seems to lean towards.--[[User:Pudder|Pudder]] ([[User talk:Pudder|talk]]) 12:32, 28 August 2014 (UTC)

Agreed. It is very in-characcter for Black Hat to simply want to mess with people, and would be very out of place to care about such trivialities as points. Ima change the mouseover description now.[[Special:Contributions/173.245.48.97|173.245.48.97]] 16:18, 22 May 2015 (UTC)

I took the April 22 wish to mean that Black Hat would have a Pokeball that works in real life, allowing him to steal the pets of random strangers on the street.[[Special:Contributions/173.245.52.124|173.245.52.124]] 23:34, 27 May 2015 (UTC)
:"Hey! No stealing another Trainer's Pokémon!". Also, talk of changing friction coefficients reminds me of the GTA "Carmageddon" videos, where the wheel friction on all the cars was set to -1, leading to most of the game being filled with cars flying through the air and exploding. -Pennpenn [[Special:Contributions/108.162.250.162|108.162.250.162]] 23:30, 13 August 2015 (UTC)
::I may have used my Masterball trying to catch another trainer's Pokemon. I cracked up after it failed, but now I have no Masterball. :( {{unsigned ip|198.41.239.34}}
:::You know, there was a side series of Pokemon games that let you capture another trainer's Pokemon. It was kind of required if you wanted more than one or two Pokemon on your team. And on that day, Black Hat was mailed a copy of Pokemon Colosseum... --[[Special:Contributions/162.158.79.65|162.158.79.65]] 23:06, 14 March 2017 (UTC)

The first wish is an example of bootstrapping. I love it. [[Special:Contributions/108.162.238.76|108.162.238.76]] 23:31, 14 February 2016 (UTC)

I think the title text is a reference to the comics where he talks about Pole vaul's record involving that some records where obtain because they were nearest of equators[[Special:Contributions/108.162.229.112|108.162.229.112]] 11:22, 20 September 2016 (UTC)

It would appear, for March 7th, that this came true... [[Special:Contributions/173.245.52.96|173.245.52.96]] 00:05, 24 November 2016 (UTC)

I got rickrolled. [[Special:Contributions/162.158.62.67|162.158.62.67]] 00:50, 13 March 2019 (UTC)

I personally like these wishes: (1) The power to know all knowable things (to include a full understanding of all available trigger conditions for wishes in the universe),
(2) the ability to always win arguments with wish granting entities, including about numbers of wishes they should grant, (3) for a stone so heavy no wish could lift it, (4) to lift that stone.

(3) and (4) together form the Russell Paradox. --[[Special:Contributions/108.162.219.170|108.162.219.170]] 18:09, 27 August 2020 (UTC)

I interpreted the February 19 entry as being a joke that the US Congressional process of passing legislation is '''so''' dysfunctional that it ends up establishing laws that did not conform to the wishes of ''anyone at all''!

No one could one-up him because he could veto any wishes that could allow that to happen

if black hat wanted veto over the wishes that veto his wishes, couldn't the people who are trying to veto black hat's wishes go one level higher and veto his vetoes, holding up his second level of veto, allowing the people who want to veto black hat to veto black hat? [[User:Plushiefan4111|plushie fan]] ([[User talk:Plushiefan4111|talk]]) 21:18, 19 November 2023 (UTC)