Small ditrigonary hexacosihecatonicosachoron

The small ditrigonary hexacosihecatonicosachoron, or sidtixhi, is a nonconvex uniform polychoron that consists of 600 regular tetrahedra and 120 regular great icosahedra. 12 great icosahedra and 20 tetrahedra join at each vertex, with a small ditrigonary icosidodecahedron as the vertex figure.

Vertex coordinates
Its vertices are the same as those of its regiment colonel, the small stellated hecatonicosachoron.

Related polychora
The small ditrigonary hexacosihecatonicosachoron has the same edges as the regular small stellated hecatonicosachoron. It shares its face arrangement with the ditrigonary dishecatonicosachoron and the great ditrigonary hexacosihecatonicosachoron. Also sharing this set of faces is the dodecahedronary hexacosichoron, a uniform compound of 25 icositetrachora. Besides these three polychora, there is only one other face-transitive uniform polychoron which is not regular, namely the tesseractihemioctachoron.