>yet again I'm afraid, to the fundamental question of this thread - what was important to the creators of rock art?
Natural features of the landscape.
RA has little to do with seeing faces. The exception to prove the rule being: http://www.themodernantiquarian.com/post/33334
Which, whilst a rather spud-like face, is evidently a portrait of someone supremely enlightened, as is evidenced by the prominent thrid eye ;)