What in the World (Or Off of It) Is a Yardang?

A yardang sounds like a nautical term: “Swab down the yardang, matey, or you’ll walk the plank!” And, from certain angles, yardangs do look like boats. But they have nothing to do with the sea—they are massive geologic formations, on Earth and on Mars, that are formed by the steady erosion of rock by the wind.