People might think that clothing with rough surfaces slows down movement because the rough parts trap air. That's not always the case. By controlling the amount of roughness, it’s possible to allow air to pass more easily over the fabric. The shape of a golf ball is based on this idea: the dimples on its surface make the air spin in small circles, like mini vortexes. These spinning circles of air act like ball bearings in a machine. The overall effect is that the ball can move more easily through the air, so it flies a greater distance. In the same way, the grooves on athletes' clothing also allow smoother movement through the air.