Tetrahedron

The tetrahedron, or tet, is the simplest possible non-degenerate polyhedron. THe full symmetry version has 4 equilateral triangles as faces, joining 3 to a vertex, and is one of the 5 Platonic solids. It is the 3-dimensional simplex.

Vertex coordinates
The vertices of a tetrahedron can be given by all even changes of sign of ($\sqrt{6}$/4, $\sqrt{2}$/4, $\sqrt{2}$/4).

These arise from the fact that a tetrahedron can be constructed as the alternation of the cube.

Alternative coordinates can be derived from those of the triangle:


 * (±1/2, -$\sqrt{2}$/6, -$\sqrt{2}$/12)
 * (0, $\sqrt{3}$/3, -$\sqrt{6}$/12)
 * (0, 0, $\sqrt{3}$/4)

These are more complicated, but generalizable to simplices of any dimension.