High Quality and unusual puzzle unique to Creative Crafthouse. designed by Prof. Rick Eason of Univ Maine, Orono. The 8 pieces are all different by each haas something of an "L" shape to it. They will make a 4x4x4 cube with only 1 unique solution. There are also many other rectangular shapes that can be using fewer of the pcs. Our instruction sheet will give you 40 such challenges. Measures about 3.5" square in the base.