That's excellent, I remember you posting something about Maen Mawr's potential alignments a while back, well done for such a good capture. There's so much about these sites that has been lost, isn't there?
I think there are probably many more examples like this, but hardly anyone is looking for it now, and while some set ups may be accidental, others certainly aren't. At least some amongst these people were shadow experts. Maen Llia , in particular, is a very clever creation, almost an exhibition piece. A kind of portfolio of megalithic science, all built into one stone and it's setting.
We are not as clever as we sometimes like to think we are.
I've not considered it before Cerrig but I'm sure somewhere along the way on this forum it's been discussed, but what about stone circles with a central standing stone, could they be a type of giant sundial using the central stone to cast a shadow in the direction of the stones to the E/N/W? Just a thought but not sure about the stones to the southern section although they would cast their own shadows toward the central stone at different times of the day as well wouldn't they then give you a direct line between them, the central stone and its opposite number in the northern section.
I won't get my coat just yet :-)