Snub disicositetrachoron

The snub disicositetrachoron, or sadi, also commonly called the snub 24-cell or omnisnub demitesseract, is a convex uniform polychoron that consists of 24+96 regular tetrahedra and 24 regular icosahedra. 5 tetrahedra and 3 icosahedra join at each vertex, forming a tridiminished icosahedron as the vertex figure.

It can be constructed by alternating the vertices of a truncated icositetrachoron and then adjusting for equal edge lengths. Alternatively, it can be thought of as a diminishing of the regular hexacosichoron, where 24 vertices corresponding to the vertices of an inscribed icositetrachoron are removed. This is why an alternate valid Bowers style acronym would be idex.

Diminishing by a further set of an inscribed icositetrachoron's vertices of the snub disicositetrachoron yields a bi-icositetradiminished hexacosichoron, diminishing two such sets yields a tri-icositetradiminished hexacosichoron, diminishing three such sets yields a quatro-icositetradiminished hexacosichoron, and diminishing all four of those here remaining subsets results in the hecatonicosachoron. It turns out that all of these pairs from zero to five diminishings result in pairs of dual polychora. In particular, the snub disicositetrachoron's dual is the quatro-icositetradiminished hexacosichoron.

Vertex coordinates
The vertices of a snub disicositetrachoron of edge length 1, centered at the origin, are given by all even permutations of:
 * (±(3+$\sqrt{5}$)/4, ±(1+$\sqrt{5}$)/4, ±1/2, 0).