Does anyone know what this brainteaser is called or how it works?

[Bohandas]

I remember seeing an illusion or brainteaser in a couple of different places where it was an image of a crowd cut into three pieces that could be rearranged into another image of a crowd with a different number of people in it, despite none of the pieces having any obvious half-a-person on the edges.

I can't seem to find a copy of it on Google or Yahoo, does anybody have one they can link to?

[Strigon]

Never seen or heard of it, but I suspect it's related to the chocolate bar trick.
If so, multiple people will be made slightly thinner than they originally were, in order to create new people. Or vice versa.

[Iruka]

Something like this?

[halfeye]

Something like this?

That one is just straight up cheating, no illusion at all involved.

[Bohandas]

Something like this?

That is exactly the one. Thank you

[Peelee]

Never seen or heard of it, but I suspect it's related to the chocolate bar trick.
If so, multiple people will be made slightly thinner than they originally were, in order to create new people. Or vice versa.

I've never seen it done with chocolate before, that amused me.

Spoiler: If anyone wants an explanation

Show

[Imbalance]

I vaguely remember the people one from a long time ago. I guess I could see the transition easily enough, as what baked my noodle for the longest time was thinking that it must be a musical solution.

[Chronos]

The chocolate bar one is actually the same trick as the one with the people (though in a simpler form), but the triangle one Peelee posted is slightly different. The chocolate and people ones are both based on making each column a little bit shorter, while the triangle one is based on a line being almost straight, but bulging up slightly in one picture and down slightly in the other.

[Peelee]

The chocolate bar one is actually the same trick as the one with the people (though in a simpler form), but the triangle one Peelee posted is slightly different. The chocolate and people ones are both based on making each column a little bit shorter, while the triangle one is based on a line being almost straight, but bulging up slightly in one picture and down slightly in the other.

Not really; the chocolate bar is more or less a live-action demonstration of the triangle, but with different cuts. If you look at a freeze-frame at 1:31 and then 1:52, you can clearly see a noticeable gap, which is conveniently going to make up most of the volume as the "extra" piece. It is also slightly shorter (and readily obvious when you look at the single column they cut out right beside it), but they're trying to hide that by widening the kerf.

[factotum]

That one is just straight up cheating, no illusion at all involved.

It's not cheating at all--if you look at the cuts made and how the picture is put together, they haven't done anything "wrong"; in fact, it's arguably less of a cheat than the "cutting up chocolate" puzzle is, because in that case, you're explicitly trying to fool people into not noticing that a chunk of chocolate is actually missing. It's just a very cleverly drawn picture.