Small snubretrosnub tetrishexacositrishexacosichoron

The small snubretrosnub tetrishexacositrishexacosichoron, or sosirstuxtix, is a nonconvex uniform polychoron that consists of 1200 great icosahedra (some of which lie in the same hyperplanes, forming 600 small retrosnub disoctahedra), 600 icosahedra and 600 great dodecahedra (forming 600 compounds of one of each), 2400 octahemioctahedra and 2400 cuboctahedra (forming 2400 compounds of one of each), 600 cubohemioctahedra (forming 120 great antirhombicosahedra), 600 rhombidodecadodecahedra, and 600 small dodecicosahedra and 600 small ditrigonal dodecicosidodecahedra (forming 600 compounds of one of each).

Two great icosahedra (two compounds), one icosahedron and one great dodecahedron (two compounds), four octahemioctahedra and four cuboctahedra (eight compounds), one cubohemioctahedron (one compound), five rhombidodecadodecahedra, and five small dodecicosahedra and five small ditrigonal dodecicosidodecahedra join at each vertex.

It can be obtained as the blend of 5 small dipentary dishecatonicosihexacosidishecatonicosachora and 5 small dipentary dishecatonicosihexacosihecatonicosachora. In the process, some of the octahemioctahedron and cuboctahedron cells blend out.

Vertex coordinates
Its vertices are the same as those of its regiment colonel, the small diretrosnub disnub decahecatonicosadishexacosichoron.