Enneagonal-square antiprismatic duoprism

The enneagonal-square antiprismatic duoprism or esquap is a convex uniform duoprism that consists of 9 square antiprismatic prisms, 2 square-enneagonal duoprisms and 8 triangular-enneagonal duoprisms. Each vertex joins 2 square antiprismatic prisms, 3 triangular-enneagonal duoprisms, and 1 square-enneagonal duoprism.

Vertex coordinates
The vertices of an enneagonal-square antiprismatic duoprism of edge length 2sin(π/9) are given by: where j = 2, 4, 8.
 * $$\left(1,\,0,\,±\sin\frac\pi9,\,±\sin\frac\pi9,\,\frac{\sqrt[4]8\sin\frac\pi9}2\right),$$
 * $$\left(\cos\frac{j\pi}9,\,±\sin\frac{j\pi}9,\,±\sin\frac\pi9,\,±\sin\frac\pi9,\,\frac{\sqrt[4]8\sin\frac\pi9}2\right),$$
 * $$\left(-\frac12,\,±\frac{\sqrt3}2,\,±\sin\frac\pi9,\,±\sin\frac\pi9,\,\frac{\sqrt[4]8\sin\frac\pi9}2\right),$$
 * $$\left(1,\,0,\,0,\,±\sqrt2\sin\frac\pi9,\,-\frac{\sqrt[4]8\sin\frac\pi9}2\right),$$
 * $$\left(\cos\frac{j\pi}9,\,±\sin\frac{j\pi}9,\,0,\,±\sqrt2\sin\frac\pi9,\,-\frac{\sqrt[4]8\sin\frac\pi9}2\right),$$
 * $$\left(-\frac12,\,±\frac{\sqrt3}2,\,0,\,±\sqrt2\sin\frac\pi9,\,-\frac{\sqrt[4]8\sin\frac\pi9}2\right),$$
 * $$\left(1,\,0,\,±\sqrt2\sin\frac\pi9,\,0,\,-\frac{\sqrt[4]8\sin\frac\pi9}2\right),$$
 * $$\left(\cos\frac{j\pi}9,\,±\sin\frac{j\pi}9,\,±\sqrt2\sin\frac\pi9,\,0,\,-\frac{\sqrt[4]8\sin\frac\pi9}2\right),$$
 * $$\left(-\frac12,\,±\frac{\sqrt3}2,\,±\sqrt2\sin\frac\pi9,\,0,\,-\frac{\sqrt[4]8\sin\frac\pi9}2\right),$$

Representations
An enneagonal-square antiprismatic duoprism has the following Coxeter diagrams:
 * x9o s2s8o (full symmetry; square antiprisms as alternated octagonal prisms)
 * x9o s2s4s (square antiprisms as alternated ditetragonal prisms)