### 13.16.2 Tetrahedrons: tetrahedron pyramid

The tetrahedron (or pyramid) command takes as arguments three or four points.

When given three points A, B and C as arguments, tetrahedron returns and draws the regular tetrahedron given by:

- One edge is AB.
- One face is in the plane ABC, on the same side of line AB as is C.
- The tetrahedron is on the side of plane ABC that makes the points A, B and C counterclockwise.

Input:

tetrahedron([-2,0,0],[2,0,0],[0,2,0])

or:

pyramid([-2,0,0],[2,0,0],[0,2,0])

Output:

Input:

tetrahedron([-2,0,0],[2,0,0],[0,2,0],[0,0,2])

Output: