Bi-icositetrareplenished grand hexacosichoron

The bi-icositetrareplenished grand hexacosichoron, or birgax, is a nonconvex noble scaliform polychoron that consists of 48 trireplenished great icosahedra. Six cells join at each vertex.

It can be formed from the grand hexacosichoron in a similar way as its conjugate, the bi-icositetradiminished hexacosichoron, can be derived from the hexacosichoron, by removing 48 great icosahedral pyramids corresponding to the vertices of 2 inscribed great icosahedra. Removing only 1 set of 24 vertices instead results in the retrosnub disicositetrachoron.