examples of dunes
Dune: accumulation of sand transported by the wind, found in deserts and along coasts.
longitudinal dunes 
Narrow elongated dunes that form when the wind blows in two convergent directions.
transverse dunes 
Dunes that form perpendicular to the direction of the wind.
chain of dunes 
Dunes aligned in the same direction, parallel to the wind.
parabolic dune 
Crescent-shaped coastal dune whose arms point into the wind; vegetation often keeps it in place.
complex dune 
Star-shaped dune that forms where winds blowing in various directions meet.
crescentic dune 
Moving crescent-shaped dune whose arms extend in the same direction as the wind.