From Tom's original listing :
"There are 8 rectangular pieces that are connected into pairs to form 4 funny cubes. The connection allows them rotate against each other. The objective is to place the pieces into a square frame, the bottom half in the frame and the top half above the frame. Both top and bottom are to form a square. The photographs shows the top and bottom views of the four Funny Cubes. (I used pieces from 2 puzzles to show tops and bottoms. But which is the top and which is the bottom?) The woods that I used from left to right are Bubinga, Holly, Indian Rosewood, Purpleheart, Honduran Rosewood, Canarywood, Yellowheart and Peruvian Walnut."