Small rhombic trisicositetrachoron

The small rhombic trisicositetrachoron, or sirti, is a nonconvex uniform polychoron that consists of 24 small rhombihexahedra, 24 quasitruncated cuboctahedra, and 24 cuboctatruncated cuboctahedra. One small rhombihexahedron, two quasitruncated cuboctahedra, and two cuboctatruncated cuboctahedra join at each vertex.

It can be constructed as a blend of three tesseractihexadecaquasitruncated prismatotesseractihexadecachora. In the process the truncated octahedra blend out, while the octagonal prisms blend into small rhombihexahedra.

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