Cube to tetrahedron
Cut cube in two pieces from which tetrahedron can be
This puzzle came to my mind around 1996 and about that time I also found a
solution. I do not know if anybody else discovered this puzzle before or after
that date. Probably, I am not the first, but it is possible.
By the way, this puzzle has (almost) nothing to do with the third Hilbert
Solution is here