Been looking at this in stereo. So very cool.

Good observations 'bout the white on rim and tires.

These are hazcams, so they are unfiltered. Notice the light substrate and background outcrop are of similar brightness. Looking forward to Pancam raw images (via MER2003 Image Workbench) and putting together some crazy color combinations.

Check out how the tires have formed the substrate into little chunks. Loafs? Blocks? Where's my thesarus? Is this like flour or playdough? Sorry to keep harping on it, but, gypsum....anhydrite...sulfosalts...

Good cohesion on the upper unit, it's holding a nice 90 degree face. We'll see how that falls apart over the next sol or so.

Don't see any of those dang spheroids in-situ sub-surface, unless they got pushed in or pulverized. I'll keep look'n and think'n.