In geometry, a simplex is a generalization of the notion of a triangle or tetrahedron to arbitrary dimensions. The simplex is so-named because it represents the simplest possible polytope in any given dimension. For example,a 0-dimensional simplex is a point,
a 1-dimensional simplex is a line segment,
a 2-dimensional simplex is a triangle,
a 3-dimensional simplex is a tetrahedron, and
a 4-dimensional simplex is a 5-cell.
The four simplexes that can be fully represented in 3D space.
A triangle is a polygon with three corners and three sides, one of the basic shapes in geometry. The corners, also called vertices, are zero-dimensional points while the sides connecting them, also called edges, are one-dimensional line segments. The triangle's interior is a two-dimensional region. Sometimes an arbitrary edge is chosen to be the base, in which case the opposite vertex is called the apex.
The Flatiron Building in New York is shaped like a triangular prism