A nice model not in the book is to take a regular icosahedron, and build
a yellow pyramid on each of eight faces chosen so that their eight apexes
are the vertices of a cube. (By duality, if you built all 20 pyramids,
you would get the vertices of a dodecahedron, but here you are choosing
just eight.) Any height pyramid can be used to locate a cube's vertices,
(including negative or zero height) but with the yellow pyramid, you can
add blue struts to build the cube and see that six of the icosahedron's
edges lie in its face planes.
