### 12.8.4 Parallelograms in space: parallelogram

See section 11.9.4 for parallelograms in the plane.

The parallelogram command takes three points as arguments.

The parallelogram command returns and draws a parallelogram. If the arguments are A, B and C, then the parallelogram has the form ABCD.
Input:

A := point(0,0,0); B := point(3,3,3);
C := point(0,0,3)

then:

parallelogram(A,B,C)

Output:

The parallelogram command takes an optional fourth argument, which is a variable the fourth vertex is assigned to.
Input:

parallelogram(A,B,C,D)

then:

coordinates(D)

Output:

[-3,-3,0]