The application of these techniques could be viewed as a way of answering questions about pictures. However, their application tends to be trivial. Why? Partly because of the traditional emphasis of quadric surfaces-which happen to be easy to sketch. A pair of interesting pictures is presented by Gilbert Strang on the cover of his new calculus book [10]. Professor Strang presented these plots during the panel discussion, "Calculus for the Twenty-First Century," at the 1990 AMS/MAA