Extra Man Sliding Puzzle Explained

by Rob Mayoff

I received the following puzzle in e-mail:

Extra Man Sliding Puzzle

(The animation starts after ten seconds.)

At the start, there are twelve men in the image. After the two sections change places, there are thirteen men. The puzzle is figuring out where the thirteenth man came from.

To understand where the extra man comes from, try playing with the following two Flash applets.