Close examination of the skin of a fast-swimming shark appears to confirm Langley's aerodynamically efficient Riblet concept. This view magnified 30 times, reveals that projections on the shark skin -dermal denticles- line up to form grooves similar to those that have reduced drag in wind tunnels. L83-9167: Mother Nature's riblet, this shark's dermal denticle has been magnified 3,000 times. Photograph published in Winds of Change, 75th Anniversary NASA publication (page 123), by James Schultz.