PentaPentaTope 2

thingiverse

Here are five triangular prisms combined into two hexagonal pyramids, which results in five 3-cell and ten 2-cells with zero vertices, making it the minimum simplex to construct an untruncated regular icosahedron. It's constructed using two squares joined at a right angle on each face of four triangles from five cubes, then combining five rhombic dodecahedra into one regular dodecahedron by attaching its ten pentagonal faces around the outside edges and four triangular faces on the inside.