ClipArt ETC
"An object in parallel perspective with one face in the picture plane is shown. At B is shown the top view of A with the cone of rays. C shows the picture plane detached and set forward in order that it may not interfere with the plan when revolved. D is the top view of C after the picture plane has been revolved." —French, 1911

Parallel Perspective

"An object in parallel perspective with one face in the picture plane is shown. At B is shown the top…