Moon Pi

It's this puzzle.There are 3 parts and they are offered as a set here. Buy one (1) of this design to get the whole puzzle.

Four (4) 3/8" ball bearings are required to complete the design. Steel will work fine, your local hardware store has these. Rubber is easiest to assemble, Mcmaster-Carr can hook you up. (Raw Materials/Rubber/Balls/3/8"/Neoprene). Glass is classiest but difficult to source, I don't have a link for these. (Marbles won't work, they must be precise.)

I quit stocking this design on my site because I felt that the world market was saturated for a puzzle that cost $200 and is, in the words of a world-class puzzle maven, "too difficult in the wrong way". But once in a while I get a request, and if you're mad enough to buy it and Shapeways is mad enough to sell it to you, go wild.

Instructions for assembly are here. (The phone number and address are obsolete, so please don't knock on that door if it isn't working out! Most likely, they won't be able to help.)