Octagonal-enneagrammic duoprism

The octagonal-enneagrammic duoprism, also known as ostedip or the 8-9/2 duoprism, is a uniform duoprism that consists of 9 octagonal prisms and 8 enneagrammic prisms, with 2 of each at each vertex.

The name can also refer to the octagonal-great enneagrammic duoprism.

Vertex coordinates
The coordinates of an octagonal-enneagrammic duoprism, centered at the origin and with edge length 2sin(2π/9), are given by: where j = 2, 4, 8.
 * $$\left(±\sin\frac{2\pi}9,\,±\left(1+\sqrt2\right)\sin\frac{2\pi}9,\,1,\,0\right),$$
 * $$\left(±\sin\frac{2\pi}9,\,±\left(1+\sqrt2\right)\sin\frac{2\pi}9,\,\cos\left(\frac{j\pi}9\right),\,±\sin\left(\frac{j\pi}9\right)\right),$$
 * $$\left(±\sin\frac{2\pi}9,\,±\left(1+\sqrt2\right)\sin\frac{2\pi}9,\,-\frac12,\,±\frac{\sqrt3}2\right),$$
 * $$\left(±\left(1+\sqrt2\right)\sin\frac{2\pi}9,\,±\sin\frac{2\pi}9,\,1,\,0\right),$$
 * $$\left(±\left(1+\sqrt2\right)\sin\frac{2\pi}9,\,±\sin\frac{2\pi}9,\,\cos\left(\frac{j\pi}9\right),\,±\sin\left(\frac{j\pi}9\right)\right),$$
 * $$\left(±\left(1+\sqrt2\right)\sin\frac{2\pi}9,\,±\sin\frac{2\pi}9,\,-\frac12,\,±\frac{\sqrt3}2\right),$$

Representations
An octagonal-enneagrammic duoprism has the following Coxeter diagrams:
 * x8o x9/2o (full symmetry)
 * x4x x9/2o (BC2×I2(9) symmetry, octagons as ditetragons)