Memory metals could make reality the science fiction concept of a liquid robot, as seen in the Terminator movies, but on a much, much smaller scale. At least that is the idea envisioned by the Defense Advanced Research Projects Agency (DARPA) in its latest call for research proposals that will aim to design and build such "devices". Self-repairing metals are already a reality, according to research published recently in the journal Science by a team from the University of Illinois. The researchers have developed a process for synthesizing aluminum and gold sheets that have exceedingly small crystal sizes, just 100 nanometers across. If these materials are deformed they can snap back into their original shape with the application of heat. DARPA envisages devices or bots that could squeeze through tiny cracks and then reform into their original function structure at the flick of a switch.