"Checkout is a put together puzzle designed by Stewart Coffin. When the puzzle is presented you see 11 of the 12 pieces placed in the tray forming a 4 x 4 checkerboard pattern. The 12 th piece is outside the tray and it is made up of 4 half square pieces. This would total 17 squares to be placed into the 4 x 4 frame! Impossible? No, you can rearrange the pieces to fit the frame, so the goal is to place the 12 pieces flat into the tray."