Minimal Coloring of Platonic Solids
A minimal coloring of a polyhedron is a coloring of its faces so that no two faces meeting along an edge have the same color, and the number of colors used is minimal. This Demonstration shows minimal colorings of the five Platonic solids that you can view either in 3D or as a 2D net. Sometimes the orientation reverses when blue and yellow faces are swapped. The icosahedron has a red and a blue triangle that can be swapped (see snapshots 2 and 3).