Six Pentagon Puzzle

George W. Hart

Other Puzzles

This puzzle is composed of thirty identical components, which assemble to form six pentagons that each interlock with the other five to form a hollow, snug, spherical form. Assembly is rather tricky, but fun (I think). Geometrically it is based on the "orderly tangle" of six pentagons first described by Alan Holden. The idea to use lap joints and make a puzzle from it comes from Teacher Lin and Sculptor Wu. For background on its mathematical structure, see this paper. The above version is machined from aluminum. Below is the same design in wood.

Here it is again in a lighter wood:

In case you read Dutch, this puzzle appears in Het Ultieme Puzzelboek
by Jerry Slocum and Jack Botermans (Terra lannoo, 2007, p. 70).

Thank you Jeff Slechta for machining the aluminum parts for me.