13.2.3  Drawing unit vectors in the plane: Ox_2d_unit_vector Oy_2d_unit_vector frame_2d

The Ox_2d_unit_vector command takes no arguments and draws the unit vector in the x-direction on a plane.

Example.
Input:

Output:

Similarly, the Oy_2d_unit_vector command draws the unit vector in the y direction. The frame_2d command simultaneously draws both unit vectors.