Photochromic canvas drawing with patterned light

Drawing tools using digital technology can stimulate creativity in people. For example, the Wacky Brush tool in KidPix can produce effects (such as a line of dripping paint or a line of shapes) that cannot be obtained using ordinary paper and brushes [Hickman 1991]. This feature makes it easy for people to draw pictures having a combination of patterns. Such software, however, has so far been used only with electronic displays such as LCDs and PDPs. In this paper, we propose a mechanism that would allow the user to draw such pictures while using paper as a canvas instead of electronic displays. With this mechanism, a variety of patterns can be made to appear along lines traced out by the user by moving an electronic paint brush over paper. The advantages of using paper in this way include a high degree of freedom in shape and size as well as portability.