Robotics. Shape shifters tread a daunting path toward reality.

754 From Star Trek to Star Wars to Terminator, science-fiction movies and TV series teem with morphing robots. If that vision is indeed a sneak preview of things to come, then the future of robotics is lying face down on a table in Mark Yim’s laboratory at the Palo Alto Research Center (PARC) in California. Or rather, was lying face down, because now it’s trying to stand up. First, the 30-centimeter-long, vaguely humanoid robot pushes itself up on all fours into a headdown, yogalike pose. Next, because the motors in its waist aren’t strong enough to lift its torso from that position, it places its head on the table. This frees the arms, which swing back behind the legs, giving it a more favorable mass distribution. Finally, the torso straightens up, and “Terminator 0.001” is ready for action. At the moment, standing up is about all the action this particular robot can handle. Unlike its cinematic kin, PARC’s Terminator cannot shoot people, take over the world, or (as one wag has suggested) run for governor of California. But what it does share with movie robots is the potential to change form. It is composed of 15 identical palm-sized modules, called PolyBots, versions of which are learning to reassemble themselves into sundry snake, insect, and wheel configurations and—most important—move around. Yim’s group at PARC, which consists of six full-time researchers and an everchanging cadre of college and even high school interns, is one of several teams in North America, Europe, and Japan trying to build modular, self-reconfigurable robots. Like living organisms, these machines