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.

Related polychora
The regiment of the octagonal spinoduoprism contains one other uniform member (the small ditetragonal spinoduoprism), a fissary uniform member (the small ditetragonal fissary duoprism, and 10 scaliform members.