Pic from Mars rover revealing... a beam of wood!!!

Some objective observations:

Image#1 (SOL115)


A - The same phenomenon can be observed at a much smaller scale (As is the case in countless other photographs available by NASA)
B - Same visual phenomenon caused by the exposure of the rock's lower layer.
C - As you can see in the angled/slated rock near the crater's edge, this type of rock is angular and slated in nature, and when broken or brought to the surface, it's lower layer differs in texture and color (This can be observed on earth in similar rok formations.)

Image#2 (SOL115)


A - As you can see from this angle, the rock's natural tendency is to break up in sharp angles, due to it's composition. In this particular case, the rocks near the edge of crater have a flat top layer, and a lower darker layer with a rough texture.
B - Viewing the same phenomenon from a top angle, you can see the same thing happening at a smaller scale.
C - Same phenomenon, different angle.

My opinion is that it is quite obvious it is an illusion created by light, weather, and the rock's very own nature/tendency. Something which can be observed here on earth. One needs only to look at this with logic. NASA provides many many pictures from the same general area which can be observed. Jumping to conclusions or making outrageous & uneducated guesses, only further makes the UFO community look like a bunch of tin-hat wearing conspiracy-theory clowns.