Curiosity's wheels are slowly gaining the normal damage expected from exploring an alien world. With no where on Mars to pull in for a pit stop, the rover has been pulling stunts like driving backwards to even out wear.
The photos of all six wheels are in raw colour, taken on sol 564 to check out how wear is progressing as the odometer keeps clicking up. You can just see Mount Sharp in the background. Image processing credit to Thomas Appéré.