The building unit of this puzzle is half a truncated octahedron (HTO). Truncated octahedra belong to the semi-regular group of so-called space-filling Archimedean
...Plus solids, dubbed Mecon by Richard Buckminster Fuller.
24 HTO's can form a cube-like stack and this is the goal of the puzzle. Six pieces of two types have to form a cube inside the frame.
