Scientists at the University of Washington have developed flying robots that change shape in mid-air, all without batteries, as originally published in the research journal Science Robotics. These miniature Transformers snap into a folded position during flight to stabilize descent. They weigh just 400 milligrams and feature an on-board battery-free actuator complete with a solar power-harvesting circuit. These robots actually mimic the flight of different leaf types in mid-air once they're dropped from a drone at an approximate height of 130 feet. The origami-inspired design allows them to transform quickly from an unfolded to a folded state, a process that takes just 25 milliseconds.