ocr: cover mmage Perspectice. SrudyofaChalice, Paolo Uccello, 1430-40. background image Calculation Diagram, Vilhelm Bjerknes, Dynamic Meterology and Hydrography, 1910. Sponsored by ACM SIGGRAPH 1515 Broadway, 17th Floor New York, New York 10036 USA +1.212.616.0500 +1.212.764.5537 fax