Close up of ripples in beach sand, going diagonally across the image from about (clock) 11 to 5. In the center is a lone stick, angled almost but not quite perpendicular to the ripple marks, casting a shadow on the sand.
https://cdn.fosstodon.org/media_attachments/files/113/459/718/837/906/957/original/6a8535846dc7f8bf.jpg