geometry, the Pentachoron or 5-cell is a four-dimensional object bounded by 5 tetrahedral cells. It is also known as the tetrahedral hyperpyramid or 4-Simplex. It is a 4-simplex, the simplest possible convex regular 4-polytope (four-dimensional analogue of a polyhedron), and is analogous to the tetrahedron in three dimensions and the triangle in two dimensions. The regular polychoron has 5 vertices, 10 edges, 10 faces, and 5 cells. With s being the length of each side, it has an edge length of 10s, a surface area of 5√3s^2/2, a surcell volume of 5s^3/6/√2, and a surteron bulk of √5s^4/96