Hexagonal-enneagonal duoprism

The hexagonal-enneagonal duoprism or hendip, also known as the 6-9 duoprism, is a uniform duoprism that consists of 6 enneagonal prisms, 9 hexagonal prisms and 54 vertices.

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

Vertex coordinates
The coordinates of a hexagonal-enneagonal duoprism, centered at the origin and with edge length 2sin(π/9), are given by:
 * (±2sin(π/9), 0, 1, 0),
 * (±2sin(π/9), 0, cos(2π/9), ±sin(2π/9)),
 * (±2sin(π/9), 0, cos(4π/9), ±sin(4π/9)),
 * (±2sin(π/9), 0, –1/2, ±$\sqrt{3}$/2),
 * (±2sin(π/9), 0, cos(8π/9), ±sin(8π/9)),
 * (±sin(π/9), ±sin(π/9)$\sqrt{2}$, 1, 0),
 * (±sin(π/9), ±sin(π/9)$\sqrt{4+csc^{2}(π/9)}$, cos(2π/9), ±sin(2π/9)),
 * (±sin(π/9), ±sin(π/9)$\sqrt{3}$, cos(4π/9), ±sin(4π/9)),
 * (±sin(π/9), ±sin(π/9)$\sqrt{3}$, –1/2, ±$\sqrt{3}$/2),
 * (±sin(π/9), ±sin(π/9)$\sqrt{3}$, cos(8π/9), ±sin(8π/9)).