One of the fun things that researchers at Xerox PARC have worked on for the last few years is "Smart Matter"; particularly, Modular robotics: "Instead of designing a new and different mechanical robot for each task, you just build many copies of one simple module. The module can't do much by itself, but when you connect many of them together you get a system that can do complicated things. In fact, a modular robot can even reconfigure itself" (such as a robot that can roll, slither, and walk all in one). Right now the modules are fairly clunky--5cm cubes, with only a dozen or so modules per robot--but in the long run they would ultimately like the modules to be MEMS units, more the size of pebbles or grains of sand, at which point they would be nearly unlimited chameleons of form. Besides opening up new frontiers in robotics, this would also open doors in the interface between people and machines, such as digital clay.