
A proof that 12=13. Just look at the picture and count the people. (pic) - nickb
http://www.tamu-commerce.edu/math/strange_but_true/people.gif
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tlrobinson
This is driving me crazy. Time to break out an image editor.

 _edit_ : if you can't let this go either, save yourself a few minutes:
<http://tlrobinson.net/misc/illuuusions.png>

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hhm
Some time ago I found this picture and worked on it until I could generate
similar animations on my own. It's tricky: the guy that disappears is gone not
because it's divided in two parts and both are made into different guys; but
because lots of little parts are made into different guys, so making a
disappearing complete guy. That is: lots of different parts in different guys
disappear in a very obvious way, and if you sum all of them, they complete a
single guy (it's not easy to explain, but there is not a single disappearing
guy, but a lot of tiny parts of different guys disappearing at once).

Try to make it work on paper to understand how it works. Notice that the upper
half of the "paper" should be cut in two halves, and those two halves _have_
to be of a different size.

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wallflower
Ingenious. Made my (early) morning. Reminds me of this proof: "The less you
know, the more you make" <http://tinyurl.com/yu2swe>

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henning
I don't have time to look at this carefully, but this has to be a dissection
fallacy like the ol' "64=65" one.

For geometric examples, see
<http://mathworld.wolfram.com/DissectionFallacy.html> .

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hhm
No, it's not the dissection fallacy, it's a different trick. I gave some
details on another post on this thread...

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jmzachary
The guy on the far left counts as an extra person after the shift (and the
loss of the top of his head).

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agentbleu
This guy is right! Im amazed I thought you all here were smart, it took me 60
seconds to figure it. And im a dumb arse who uses LAMP.

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TheTarquin
Wow, I definitely stared at that for 15 minutes. I know it's trickery, but
it's still pretty brain-twistingly cool.

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daniel-cussen
So it cuts a line out of like seven people and makes a thirteenth dude, right?

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hernan7
Wasn't this puzzle originally invented by Henry Dudeney like 100 years ago?

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yters
No one's seen the disappearing square trick in math class?

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hhm
I didn't... How does it work?

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yters
<http://everything2.com/index.pl?node_id=810090>

Same sort of idea - makes use of deviations in the picture that are hard to
pick out.

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hhm
Ah, but it's not it. The one in the animation is not a geometric problem, it's
more subtle (I solved two years ago, see my other comment).

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dcurtis
This is insanely cool, but...

optical illusion != proof

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zoltz
Not an optical illusion. Twelve guys really become thirteen. But they have to
pay a price for that: they're somewhat shorter, their heads are slightly
smashed in, etc. Basically the same as what happened when hunter-gatherers
switched to agriculture: more people but less healthy.

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jory
This is worse than the stuff that ends up on the reddit front-page. Please,
let's try to keep this stuff away from yc.

