A collaborative team of researchers from the University of California, Berkeley, the Georgia Institute of Technology, and Ajou University in South Korea has revealed that the unique fan-like propellers of Rhagovelia water striders—which allow them to glide across fast-moving streams—open and close passively, like a paintbrush, ten times faster than the blink of an eye.A collaborative team of researchers from the University of California, Berkeley, the Georgia Institute of Technology, and Ajou University in South Korea has revealed that the unique fan-like propellers of Rhagovelia water striders—which allow them to glide across fast-moving streams—open and close passively, like a paintbrush, ten times faster than the blink of an eye.[#item_full_content]