Octagonal spinoduoprism

The octagonal spinoduoprism, or ondip, is a nonconvex uniform polychoron that consists of 64 regular tetrahedra, 128 triangular prisms, and 64 cubes. 2 tetrahedra, 6 triangular prisms, and 4 cubes join at each vertex.

It was discovered in March 2006, constructed as a blend of 4 small disprismatotesseractihexadecachora. Its vertex figure is in turn a blend of two vertex figures of the small disprismatotesseractihexadecachoron. It has the same symmetry as the octagonal duoprism.