I have loads of photos of rock piles, especially small and relatively homogeneous ones from what some people call cairn sites, large areas covered with pile after pile, all of them about the same width and height. But some have these anomalous stones or arrangements of stones. The bottom two pictures, from a 'cairn site' in Monroe County, are from a photo CD of very low quality, and the color is poor. The first one, from Oley Hills, shows a rock pile in which there is a section that stands out. The stones seem to have been arranged in a radial shape in the middle of an otherwise flat-stacked pile.
In the one below, a very odd-shaped stone is used near the bottom. While the other stones in this one aren't completely standard either, the pile somehow seems focused on that one odd rock.
Here again we have mostly flat stones with one notable exception, this time stuck in the middle.
As I said, these piles are the exception. I can show you twenty piles or more from the same site as the last two, none of which show anomalous stones the way these do. I've seen other piles, too, that are probably better examples of what I'm trying to show than these are.
But Norman's picture reminded me of that sort of thing. It may just be a thing that happens by chance, but it doesn't hurt to look at all these details.