A dry lake bed that is surprisingly flat, with only a four centimeter height differential between the north and south ends. When the heavy desert rains come, water pours onto the lake bed, forming a very shallow lake. Due to the hot temperatures of the region, the water evaporates, leaving behind a layer of soft, very slick mud. There is a theory that high winds move the rocks at this time, the thin layer of mud acting as a lubricated surface. however, The fact that some stones move and others do not, or that some will simply change direction... makes the wind theory slightly suspect.
Dirty and Gross