Henry Bradlow holds an RC controller and a horribly cracked Moto X, but he's only gripping these devices in case something goes wrong with his demo. When Bradlow, the CTO and co-founder of Lily Robotics, gives the go sign, Nghia Ho, the company's computer vision engineer, flings a drone straight up into the air. It rises, and then immediately begins to fall. For a split second, it appears as though this 3D-printed prototype with a camera attached is about to shatter into a thousand pieces. But just as the drone starts to descend, Lily's four rotors flick on. The machine steadies itself in mid-air, then rises about twenty feet and hangs there, awaiting instructions.