From eBay: BUY NOW: Bisected Tetrahedron
Print your own with these files: Five Screw Puzzles
See the related Tirsected Cube Puzzle
Bisected Tetrahedron Puzzle: two identically shaped pieces interlock to form the famous four faced platonic solid in this ingenious dissection puzzle. The tetrahedron is sliced following a helical path along the 2-fold symmetry axis (middle of one edge to its opposite), creating a smooth disassembly, and a smooth but mildly challenging reassembly. Fun math today from puzzle maker, artist, and mathematician George Hart.