Jessen Icosahedron

sketchfab

This distinctive characteristic of this non-convex 20-sided polyhedron is that all its dihedral angles measure 90 degrees, encompassing both concave angles (blue edges) and convex angles (brown edges). It's also classified as a "shaky polyhedron," with explanations available at mathworld and wikipedia. This model was generated using vzome. A vzome model, a Collada DAE model, and an OFF model are included in the zip download file.