Great 10-3 double step prism

The great 10-3 double step prism is a convex isogonal polychoron that consists of 10 tetragonal disphenoids, 20 phyllic disphenoids and 80 irregular tetrahedra of two kinds obtained as the convex hull of two orthogonal 10-3 step prisms.

This polychoron cannot be optimized using the ratio method, because the solution (a/b = (3-$\sqrt{5}$)/2) would yield a biambodecachoron instead.