Can someone tell me how this works?

[Kevin43]

As near as I can figure, the shift steals enough parts from each person to create a new person but I can't really tell.
http://www.ebaumsworld.com/peoplecount.html

[Ryan2003]

the person in the very back 1st row 3rd column gets moved to the end. When he gets moved to the end he has a full set of legs, When he's in the middle he has half a pair of legs. You can obviously tell this as he is the shortest person(The middle guy) in the entire picture