5-cell

In geometry, the 5-cell is a four-dimensional object bounded by 5 tetrahedral cells. It is also known as a C₅, pentachoron, pentatope, pentahedroid, or tetrahedral pyramid. It is a 4-simplex, the simplest possible convex regular 4-polytope (four-dimensional analogue of a Platonic solid), and is analogous to the tetrahedron in three dimensions and the triangle in two dimensions. The pentachoron is a four dimensional pyramid with a tetrahedral base.