Yes, interestingly presented. Just because these drawings were made eons ago, we musn't forget that the artists were intelligent people, and really it isn't a huge leap in understanding to start thinking about representing the thousands of dots we see in the sky in shapes reminiscant of earthly sustenance.
Again, angles weren't difficult to define either - "so many thumbs to the left and six little fingers high" kind of stuff - a sense of proportion would have helped. Not too difficult. Very cool nontheless!
What I don't really understand, though, is how there were so many caves around whos entrances and topography were perfectly aligned to the sun on just two occasions - soltice and equinox. I can imagine that light would have flooded these caves on certain days and not others, but almost certainly for days if not weeks either side of solstice or equinox - not just "on the day", which is what I think they were trying to convey.