Missing person illusion puzzle with 12 and 13 figures

[Huckleberry]

I don't know if this has been posted before or not. Looking at this puzzle one way I see 12 people, and after two pieces are transposed I see 13 people. Where does this person come from/go to? Am I missing something simple? Anyone got any ideas?

http://www.ebaumsworld.com/peoplecount.html

 

[mattmns]

I think I figured it out, well the head at least.

Check out the lady at the far left on the bottom. Her hair is removed, and put on top of a girl in the middle, but it is not replaced. While the girl in the middle uses her hair on another person.

 

[Huckleberry]

I notice some of the other people get larger or smaller when the images are transposed. Could this space account for the extra person? I'm not sure. It's not like the people themselves are moving. How do all the parts get in the same place, or reabsorbed into several other figures with only moving two still images?

 

[TenaliRaman]

Note that there are 5 columns (slanted) of ppl.
The first, third, fourth and fifth columns have invariant number of ppl, that is there number doesn't change even when the pieces get interchanged.

However the second column changes from two to three. Try to see how this trick is managed. (Its should be easier now since you are looking at a local action instead of global change).

-- AI

 

[Jimmy Snyder]

The thirteenth person is a kind of Frankenstein's monster made up of bits and pieces of the other 12. You can see one person who has lost their hair and other who has lost a major part of their shoes, etc. Getting that to work with only a shift of the top half of the image is very clever.