Three Piece Interlocking Tetrahedron Puzzle (Stewart Coffin)

This is a simple three piece puzzle based on a design by Stewart Coffin. The solution is somewhat counterintuitive making it more difficult than the low parts count would suggest.

I added .2mm slop, but one can easily alter that value in the Openscad file. I did not make it parametric, so to adjust the clearance, one must change every ".9" in the code. Sorry.