The photo of this wind- and water-sculpted granite was taken on the beach at LaDigue, Seychelles, with a Nikon D200 and a Nikkor 18-200 mm VR lens at 18 mm. The exposure was f/11 and 1/1500 sec. The color change at the high tide limit is understandable, but what explains the near-vertical surface feature that resembles ocean waves?