Enneagonal-dodecagonal duoprism

The enneagonal-dodecagonal duoprism or etwadip, also known as the 9-12 duoprism, is a uniform duoprism that consists of 9 dodecagonal prisms and 12 enneagonal prisms, with two of each joining at each vertex.

This polychoron can be subsymmetrically faceted into a triangular-square triswirlprism, although it cannot be made uniform.

Vertex coordinates
The coordinates of an enneagonal-dodecagonal duoprism, centered at the origin and with edge length 2sin(π/9), are given by: where j = 2, 4, 8.
 * $$\left(1,0,±\left(1+\sqrt3\right)\sin\frac\pi9,±\left(1+\sqrt3\right)\sin\frac\pi9\right),$$
 * $$\left(1,0,±\sin\frac\pi9,±\left(2+\sqrt3\right)\sin\frac\pi9\right),$$
 * $$\left(1,0,±\left(2+\sqrt3\right)\sin\frac\pi9,±\sin\frac\pi9\right),$$
 * $$\left(\cos\left(\frac{j\pi}9\right),±\sin\left(\frac{j\pi}9\right),±\left(1+\sqrt3\right)\sin\frac\pi9,±\left(1+\sqrt3\right)\sin\frac\pi9\right),$$
 * $$\left(\cos\left(\frac{j\pi}9\right),±\sin\left(\frac{j\pi}9\right),±\sin\frac\pi9,±\left(2+\sqrt3\right)\sin\frac\pi9\right),$$
 * $$\left(\cos\left(\frac{j\pi}9\right),±\sin\left(\frac{j\pi}9\right),±\left(2+\sqrt3\right)\sin\frac\pi9,±\sin\frac\pi9\right),$$
 * $$\left(-\frac12,±\frac{\sqrt3}2,±\left(1+\sqrt3\right)\sin\frac\pi9,±\left(1+\sqrt3\right)\sin\frac\pi9\right),$$
 * $$\left(-\frac12,±\frac{\sqrt3}2,±\sin\frac\pi9,±\left(2+\sqrt3\right)\sin\frac\pi9\right),$$
 * $$\left(-\frac12,±\frac{\sqrt3}2,±\left(2+\sqrt3\right)\sin\frac\pi9,±\sin\frac\pi9\right),$$

Representations
An enneagonal-dodecagonal duoprism has the following Coxeter diagrams:
 * x9o x12o (full symmetry)
 * x6x x9o (dodecagons as dihexagons)