If we were organised this page would contain a wealth of information and background on the Tetrahedrane puzzle. But we're not organised so it is short and sweet for now. Please check back later.
The short version is that Tetrahedrane is our take on Oskar's Screwballs design previously released by him as a 3D printed puzzle.
With precisely machined stainless rods and brass vertices, this metal version really shows off the design to it's fullest.
Wikipedia has a nice page on Tetrahedrane