... Other conics, besides circles, can be used to specify coordinate positions. For example, using concenhic ellipses instead of circles, we can give coordinate positions in elliptical coordinates. ... COOK, R. L. AND K. E. TORRANCF (1982). "A Reflectance Model for Computer Graphics& quot;, ACM Transncfions on Graphics, 1(1), pp. 7-24. CCXIK, R. L., T. PORTER, AND L CARPENTER ... a circle in the xy plane with center at the coordinatc origin could be defined in parametric form as Other parametric fomx are also possible for describing circles and circular arcs. Curved...