Small pyramidic swirlprism

The small pyramidic swirlprism or spysp is a nonconvex noble scaliform polychoron. It consists of 240 pentagonal pyramids in 120 coplanar pairs. It is notable for being concave, that is, it is not convex yet its entire surface is exposed.

It can be formed by blending a small swirlprism with a faceted hexacosichoron.

Its vertex figure is the dual of the vertex figure of gisp.