Rock art and astronomical lines are highly dubious on the whole. There've been a number of attempts to show linearity and sight-lines thru the years, but these in themselves are highly selective and, where students reckon there to be a potential correlate, in actuality have degrees of improbability greater than a statistician on acid would give you! There's exceptions of course, but in this line of enquiry, unless the findings truly hits you in the face I'd assume logical thinking is over-riding, nay 'interfering', with the non-linear nature of most CnRs.