Painting with Frost

Subtle variations in color look like brush strokes as the lightly frosted terrain reflects light. These variations provide a backdrop to some exotic features referred to colloquially as "spiders."

The radial channels branching out from a central depression are formed when the seasonal layer of dry ice turns to gas in the spring and erodes the surface, which is a uniquely Martian landform.

http://photojournal.jpl.nasa.gov/catalog/PIA21214