Here's another version with thinner tetrahedra. 20 units per edge. Took a few iterations to get the proportions right. Parts are on order, 720 pieces total. Honest assessment: looks decent in renders but the structure is weak in real life. The hinges flex too much and the whole thing wobbles. I've got a more rigid version designed now - thicker edges, better bracing - but this one was worth testing. Built with regular plates and tiles, hinges at the vertices. No Technic. The math checks out,...