Jouko Koskinen

When the pentagonal faces of a spherical icosidodecahedron are replaced by pentagrams, the result is a set of ten great circles. At each intersection only two circles meet. The total number of intersections is 90. A set of 6, 12 or 30 intersections can be chosen to be the vertices of an octahedron, a cuboctahedron or an icosidodecahedron, respectively. The sets of 6 and 12 intersections can be chosen in 20 and 5 ways. The edges of one of each type of the mentioned polyhedra are represented by yarns: red yarn for the octahedron, blue yarn for the cuboctahedron and green yarn for the icosidodecahedron. The circles are steel wires. Trichromatic Glasses glasses help visitors see one polyhedron brighter than the others.