If you want to see the future of 3-D printing, ask Stefanie Mueller for a demo. A computer scientist at MIT, Mueller's work has involved projects like developing a laser-cutting system to make delicate, 3-D printed origami. Now, Mueller and a team at MIT's Computer Science and Artificial Intelligence Lab are introducing a new kind of 3-D printable ink that makes it possible to recolor 3-D objects after they've been printed. The method, called ColorFab, combines a 3-D printing interface and a special type of 3-D printable ink that changes colors when activated by light. Together, the system makes it possible to dynamically change and customize an object's appearance many times.