To make your own model, start with a **b2 **or** b3** regular
icosahedron for its core and keep in mind that at each vertex there are
two opposite icosahedra and five octahedra connecting them. Around
each edge is one icosahedron and two octahedra. The components in
the 3D projection are flattened more and more as you get further from the
center. You may recognize some of the flattened octahedra as triangular
antiprisms from Unit 1.2 and some of the flattened icosahedra appear in
Exploration 2A. There are also 30 totally flat icosahedra and 60
totally flat octahedra on the surface. Here are closeups along the
5-fold and 3-fold symmetry axes:

This model was constructed and photographed by Mira Bernstein and Vin
de Silva.