As an undergraduate, Jovan Popovic found that animated illustrations of math-problem solutions helped him master complex concepts. But that animation is tedious and expensive. So Popovic, who grew up in Yugoslavia and is now an MIT assistant professor, set out to make it easy and affordable for neophytes and professionals alike. He developed software that works like the drag-and-drop feature in word-processing programs. To show, say, a hat flipping through the air and landing on a coat rack, the creator simply mores the hat with a computer mouse, and Popovic’s program generates the appropriate animated movement. “He has made significant progress toward solving one of the key problems in animation: to make it look natural and control it at the same time,” says Andrew Witkin of Pixar Animation Studios. The entertainment industry should benefit, but Popovic wants to reach teachers, children, and educational filmmakers. He isn’t sure whether to license his software or start a company to develop it. Up next: programs that create animation in response to verbal commands.