came across some knotted tetrahedrons (in celebration of the dragon boat festival) on https://bbs.zhongguojie.org/, the sepak takraw style tetrahedron reminded me strongly of Struktor’s work but a search of the forum only brought me a bipyramidal shape. I need/want more angles or a schematic to see what’s going on. 
There was also a pan chang based tetrahedron. Alas, no instructions (yet?)
