Are you being oblique?

A piece of Mars: Barchan, or crescent dunes, are generally thought to form from winds blowing from a single direction. Reality isn’t usually that nice. Here are two barchans with crescent-shaped slip faces on their eastern (right) sides, indicating that the main dune-building winds blow from the west (left). However, ripples, an elongated dune arm,

Relentless wind

A piece of Mars: This is what the relentless work of the wind can do. That vaguely circular structure in the center of the image is probably the remains of a ~150 m diameter impact crater. Since it formed, it’s been at least partially buried in dust. That dust was probably scoured from elsewhere on