Ralph Bagnold, an early pioneer of dune studies, remarked that—compared to the nearly static chaos that seems to characterize slowly crumbling, weathering landscapes—sand dunes can “move inexorably, in regular formation, over the surface of the country, growing, retaining their shape, even breeding, in a manner which by its grotesque imitation of life, is vaguely disturbing to an imaginative mind.” Perhaps more so, if we’re on Mars?