Several possible targets of study for rover Sojourner's Alpha Proton X-Ray Spectrometer (APXS) instrument are seen in this image, taken by the Imager for Mars Pathfinder (IMP) on Sol 2. The smaller rock at left has been dubbed "Barnacle Bill," while the larger rock at right, approximately 3-4 meters from the lander, is now nicknamed "Yogi." Barnacle Bill is scheduled to be the first object of study for the APXS. Portions of a petal and deflated airbag are also visible at lower right. http://photojournal.jpl.nasa.gov/catalog/PIA00629