Great transitional 13-5 double step prism

The great transitional 13-5 double step prism is a convex isogonal polychoron that consists of 26 bilaterally-symmetric digonal scalenohedra, 13 tetragonal disphenoids and 52 irregular tetrahedra obtained as the convex hull of two orthogonal 13-5 step prisms.

The ratio between the longest and shortest edges is 1:2.98928.

Vertex coordinates
Coordinates for the vertices of a great transitional 13-5 double step prism are given by: where a ≈ 0.1342686996111878133300549, b ≈ 2.0223594019664291689707605 and k is an integer from 0 to 12.
 * (a*sin(2πk/13), a*cos(2πk/13), b*sin(10πk/13), b*cos(10πk/13)),
 * (b*sin(2πk/13), b*cos(2πk/13), a*sin(10πk/13), a*cos(10πk/13)),