See section 12.9.1 for squares in the plane.
The square command takes as arguments three points, A, B and P.
square returns and draws and returns the square with one side
AB and the remaining sides in the same half-plane as
P.
Input:
then:
Output:
The square command also optionally takes two more arguments,
variable names to assign to the two new vertices.
Input:
then:
Output: