Rectified small ditrigonary hexacosihecatonicosachoron

The rectified small ditrigonary hexacosihecatonicosachoron, or rissidtixhi, is a nonconvex uniform polychoron that consists of 600 regular octahedra, 120 small ditrigonary icosidodecahedra, and 120 great icosidodecahedra. 2 small ditrigonary icosidodecahedra, 3 great icosidodecahedra, and 3 octahedra join at each ditrigonal prismatic vertex. As the name suggests, it can be obtained by rectifying the small ditrigonary hexacosihecatonicosachoron.

Vertex coordinates
The vertices of a rectified small ditrigonary hexacosihecatonicosachoron of edge length 1 are given by all permutations of: along with all even permutations of:
 * $$\left(0,\,0,\,±\frac{\sqrt5-1}{2},\,±\frac{1+\sqrt5}{2}\right),$$
 * $$\left(0,\,±1,\,±1,\,±1\right),$$
 * $$\left(±\frac12,\,±\frac12,\,±\frac12,\,±\frac32\right),$$
 * $$\left(±\frac12,\,±\frac12,\,±\frac{\sqrt5}{2},\,±\frac{\sqrt5}{2}\right),$$


 * $$\left(0,\,±\frac{3-\sqrt5}{4},\,±\frac{3+\sqrt5}{4},\,±\frac{\sqrt5}{2}\right),$$
 * $$\left(0,\,±\frac{\sqrt5-1}{4},\,±\frac32,\,±\frac{1+\sqrt5}{4}\right),$$
 * $$\left(±\frac{3-\sqrt5}{4},\,±\frac{\sqrt5-1}{4},\,±\frac{1+\sqrt5}{2},\,±\frac12\right),$$
 * $$\left(±\frac{3-\sqrt5}{4},\,±\frac12,\,±\frac{3+\sqrt5}{4},\,±1\right),$$
 * $$\left(±\frac{\sqrt5-1}{4},\,±\frac{1+\sqrt5}{4},\,±\frac{\sqrt5}{2},\,±\frac12\right),$$
 * $$\left(±\frac12,\,±\frac{\sqrt5-1}{2},\,±\frac{3+\sqrt5}{4},\,±\frac{1+\sqrt5}{4}\right).$$

Related polychora
The rectified small ditrigonary hexacosihecatonicosachoron is the colonel of the largest non-snub regiment of uniform polychora, containing a total of 157 members, plus three compounds and three fissaries. Jonathan Bowers divides the rissidtixhi regiment into twenty subcategories.

The rectified small ditrigonary hexacosihecatonicosachoron contains the vertices and edges of the decagonal-decagrammic duoprism, the quasitruncated dodecadodecahedral prism, and the rectified icositetrachoron.