Small transitional 15-4 double step prism

The small transitional 15-4 double step prism is a convex isogonal polychoron that consists of 30 tetragonal antiwedges, 15 rhombic disphenoids, and 30 phyllic disphenoids. 6 tetragonal antiwedges, 2 rhombic disphenoids, and 4 phyllic disphenoids join at each vertex. It can be obtained as the convex hull of two orthogonal 15-4 step prisms.

The ratio between the longest and shortest edges is 1:$$\frac{\sqrt{665+247\sqrt5}}{19}$$ ≈ 1:1.83631.