This is a famous puzzle designed by Stewart Coffin 40 years ago. Wood copies must be made with great accuracy and have become sought-after collectors items selling for several hundred dollars. This leads to the current state of affairs where many people have never even seen this excellent puzzle. I had never seen one, so I exported the pieces from BurrTools and printed out a copy. Now anyone can order an inexpensive copy of this puzzle.
Six pieces, all different, assemble into a cube with side 32mm or about 1.25 inches.
For some reason Shapeways has been unable to dye this model, although as you see I was able to dye it myself with no problems. Thus the model is only available now in Polished White, Strong and Flexible.