It started with tennis balls. As a former collegiate tennis player, Daniela Rus habitually rolls two tennis balls around in her hand as she paces her office. As a robotics researcher at Dartmouth College, she wondered why the tennis balls shouldn't be able to roll themselves around.
She soon determined that electromagnets didn't have enough lifting power to solve the tennis-ball problem. However, her question led to a decade-long research program into the challenges of designing robots that reconfigure themselves to perform different tasks.