20-8 gyrochoron

The 20-8 gyrochoron, also known as the double helix 20, is a convex isochoric polychoron and member of the gyrochoron family with 20 monolaterotriangulated pentagonal prisms as cells.

Each cell of this polychoron has mirror symmetry, with 2 pentagons, 4 tetragons, and 2 triangles for faces.