I've been imagining this piece for some time.
I felt intuitively there might be a dynamic relationship as I had perceived between the sphere and the cube,with the earlier pieces "Squaring the Circle"etc. The energy becomes palpable when the two shapes approach volume congruency. I have no idea why this occurs,but my curiosity and intuition keep leading me on...
The sphere is 4" in diameter and made of stainless steel.
The tetrahedron is made of silicon bronze.