This is a new puzzle, designed/discovered by Saul Schleimer and myself. It is based on the 120-cell, one of the 4-dimensional regular polytopes, the analogues of the 3-dimensional regular polyhedra (the cube, tetrahedron, octahedron and so on). The goal is to assemble the 5 identical pieces shown in the first picture into the ring-like structure shown in the others. Each of the five pieces is made from six dodecahedral cells, giving the puzzle its name. Shapeways shop YouTube video Cheers, Henry