Overhang

A Piece of Mars: There’s a fabric of erosion in this 1×1 km (0.62×0.62 mi) scene, with the main wind blowing from lower right to upper left (and if you look carefully you’ll see there’s a second, subtler fabric a bit clockwise from that one). The result is a landscape strewn with streamlined rock called yardangs. The darkest areas are shadows from rock faces scoured by the wind so deeply that they’ve been undermined until there’s overhang. Normally this would lead to collapse features, like rock piles, but you don’t see those here. That’s an indication that the rock here is easily eroded and fine-grained, so that as it’s eroded, it’s simply carried off by the wind. (HiRISE ESP_052384_1800, NASA/JPL/Univ. of Arizona)