Most debris on crater walls slides straight downhill. In this HiRISE image we see examples of boulders that have bounced downhill, not necessarily vertically.
A prominent example looks like a dotted line from the top of the crater wall where the boulder took off to the crater floor where it finally came to rest.
Numerous boulders have slid partway down toward the crater floor, which is covered by sand dunes. This is actually a small crater (approximately 1 kilometer wide) within an unnamed but much larger approximately 30 kilometer crater.
Written by: Candy Hansen (23 December 2009)
More info and image formats at http://hirise.lpl.arizona.edu/PSP_001385_1985
Image: NASA/JPL/University of Arizona