I actually first thought of the idea of lines in space in 1966. My retrospective exhibition at Siggraph 2006 displayed a drawing I made which illustrated the notion of flying through a drawing. Even in my early plotter drawing days I was dreaming about three dimensional space. But it was thirty years before I realized the idea of lines in space. When Steve May, currently at Pixar, was working on his Ph.d at OSU, we had an ongoing dialog about lines in 3d space. Lines which could reflect light and cast shadows. Later Steve developed a technique for me which made this possible. In exchange for his code I gave him my OSU season football tickets. They were great seats. The above example called A Happy Time was created in 1996.