It's odd, but there'd been talk amongst RAfans of faint motifs being the result of something organic having been painted onto rocks, with subsequent enhanced lichen growth, before this was published.
I'm not sure about yoghurt either, but in the absence of evidence of carving/pecking, it's at least feasible I suppose. I also quite like the fact that it (the castlerigg un-spiral) adds to the general mysteriousness of the place.

Chris, at least your quotes sound rational in the article, it does n'alf make me sound like a bit of a loon. Which is fair enough I guess ;)

As far as amateur high-tech goes Whatisthat, Mr rockrich has the photogrammetry kit, and Rockandy can lay his hands on similar, but the 3d scanning stuff is waaay too expensive :(