Some more dune - river interaction. On the edge of the Tsauchab 'River', which is mostly dry, but at one time reached the Namibian coast, these are effectively arms of star dunes.
Winds here in the Namib Sand Sea are mostly southerly with easterlies blowing up the Tsauchab valley and north-easterlies blow in winter. It is the latter that create the dune arms pointing into the valley.
The flashearth image is here.