9-2 gyrochoron

The 9-2 gyrochoron, also known as mobius 9, is a convex isochoric polychoron and member of the gyrochoron family with 9 ridge-truncated edge-truncated tetrahedra as cells. It can also be constructed as the 9-4 gyrochoron. Together with its dual, it is the second in an infinite family of triangular dihedral swirlchora.

It is one of three isochoric polychora with 9 cells, the others are the 9-3 gyrochoron and the triangular duotegum.

Each cell of this polychoron has mirror symmetry, with 2 heptagons, 4 tetragons, and 2 triangles for faces, and shares a face with every other cell.

Isogonal derivatives
Substitution by vertices of these following elements will produce these convex isogonal polychora:
 * Ridge-truncated edge-truncated tetrahedron (9): 9-2 step prism
 * Mirror-symmetric heptagon (9): 9-2 step prism
 * Kite (9): 9-2 step prism
 * Isosceles triangle (9): 9-2 step prism
 * Edge (9): 9-2 step prism
 * Edge (18): 18-2 step prism
 * Vertex (9): 9-2 step prism