I read an intriguing book called "Geometric Puzzle Design" by Stewart T.
Coffin last fall. Mr. Coffin needs no introduction to wooden puzzle
fans - he is to puzzle design what M. C. Escher is to graphic arts.

The book is long on design considerations, and intentionally sketchy on
specifics. One tantalizing page shows a puzzle called the Three Pairs
Puzzle. A couple of line drawings and a cryptic description are all I
had to go on. There were no hints at all on how to assemble it!

This is, by far, the most fiendish assembly puzzle I've ever
encountered. The parts are simple enough - twelve identical pieces
glued up into three mirror-image pairs. Looks simple enough!

The puzzle is mahogany, about 3" on a side.

Scott