People sketch to work through ideas and to communicate, especially when dealing with spatial matters. AI software that could participate in sketching as people do could revolutionize education. To that end, we created CogSketch, one of the products of SILC. CogSketch is both an instrument for cognitive science research and a platform for new kinds of sketch-based educational software. Our goal when SILC started was that sketch-based educational software could be widely available to students as graphing calculators were back then. We have achieved this vision, via tight collaboration between AI researchers on the CogSketch development team and psychologists, learning scientists, and educators.