Small retrosnub disoctahedron

The small retrosnub disoctahedron, sirsido, or compound of two great icosahedra is a uniform polyhedron compound. It consists of 40 triangles (8 pairs of which form hexagrams due to following in the same plane), with five faces joining at a vertex.

It can be constructed from the pentagrammatic snub pseudodisoctahedron by replacing each small stellated dodecahedron with the great icosahedron with which it shares its edges.