Fly using half barrel roll maneuver
A composite image shows the stages of a half barrel-roll maneuver executed by a Calliphora vomitoria fly in an inverted landing. Researchers at Penn State University are studying flies’ inverted landings in hopes of engineering robotic drones that can mimic such landings. (Image courtesy of Bo Cheng, Ph.D., and Pan Liu, Department of Mechanical Engineering, Penn State University)