Perspective Rendering by Hand-Held Calculator by Pau I S. Hoffman One of the oldest ways of describing perspective compares a picture to a pane of glass through which objects beyond are viewed. If you hold your head very still and sight with one eye, a traced outline on the glass will depict what you see in accurate perspective. In fact, some ingenious devices were constructed during the Renaissance and thereafter which made use of this very principle. Early researchers and practitioners realized that there was a geometrical relationship involved here-a relationship between the object viewed and Paul S. Hoffman is scenic designer for New Jersey Public Television. He has taught all aspects of technical theatre at Denison University in Ohio and Trenton State College in New Jersey. He has also designed for the Bucks County Playhouse.