Small swirlprism

The small swirlprism or sisp, also known as the pentagonal-antiprismatic hecatonicosachoron, decafold great dodecaswirlchoron, or gadswirl 120, is a nonconvex uniform polychoron. It consists of 120 pentagonal antiprisms. It is the first in an infinite family of isogonal great dodecahedral swirlchora and also the first in an infinite family of isochoric great dodecahedral swirlchora, using a decagon for each of its 12 rings.

Isogonal derivatives
Substitution by vertices of these following elements will produce these convex isogonal polychora:
 * Pentagonal antiprism (120): Hexacosichoron
 * Pentagon (120): Hexacosichoron
 * Edge (120): Hexacosichoron
 * Edge (600): Partially-rectified small swirlprism