Pentagonal-pentagrammic concave duoantitegum

The pentagonal-pentagrammic concave duoantitegum, also known as the 5-5/3 duoantitegum, is a nonconvex isochoric polychoron with 50 star-elongated digonal disphenoids as cells.

Each cell of this polychoron has rectangular pyramidal symmetry, with 4 kites and 4 isosceles triangles for faces.