Bruce Murray Space Image Library
Lava swirls in a channel in Cerberus Palus, Mars
The original image can be viewed here. The swirls were described in a paper published in Science by Ryan Anderson and Phil Christensen:
The spiral patterns in Cerberus Palus are morphologically consistent with lava coils on Earth that form on the surface of active and stagnated pahoehoe lava flows and lava lakes. Terrestrial lava coils range from 5 cm to at least 10 m in diameter. Two types of coils have been observed in terrestrial lava flows, each with slightly different characteristics and formation processes. The first forms along distinct shear zones between two blocks of crust above flowing lava. .... The second, larger form also develops in shear zones where wrinkles in thin congealed lava skins or molten lava exuded through ephemeral shear cracks rotate slowly. .... With few exceptions, terrestrial lava coil orientation is consistent with the direction of shearing, although such shears are commonly not preserved: Clockwise-in coils record right-lateral shear, whereas counterclockwise-in coils record left-lateral shear.
Here is a series of images that provide context: