An amusement device comprises a solid cube which may be disassembled into a plurality of blocks (80, 81, 82, 83) of differing geometric shapes wherein each of the geometric shapes is formed from one or more modular units. Each modular unit comprises an isosceles right triangular prism having a triangular face formed by two legs each of which has a length A and which meet at a right angle, and a hypotenuse which has a length B, said modular unit having a depth which is equal to A, and a volume which is equal to C. Each of the differing geometric shapes is formed from one or more modular units and has a volume equal to an integral number times C, and the total volume of said solid cube is equal to 16C.