Have you ever played that old plastic or wooden puzzle called "15"?
Here it comes in fabulous digital colors on the screen of Your PocketPC.
The rules are simple : Just match the big pictures with the small one at the bottom of Your screen.
The game is played by moving a piece to the empty place and this way shuffling the pieces so the picture gets reconstructed in it's original shape.
You move a piece by clicking on it - if it's next to the empty place it will slide over it.