Compound of 20 Octahedra, sandstone

This wireframe model  is a uniform polyhedron compound of 20 octahedra with icosahedral symmetry. It shares its edge arrangement with the great dirhombicosidodecahedron, which was nicknamed "Miller's monster" (after J. C. P. Miller, who with H. S. M. Coxeter and M. S. Longuet-Higgins enumerated the uniform polyhedra in 1954). (See Wikipedia.)