Ground Patterns

There are several little designs that I see without being aware of them until I am going back over my journals and see enough pictures of the same repeated thing that I notice it. One of my favorite examples of a "ground pattern" looks something like this:I came across a elaboration of this pattern today, in Littleton, an old friend:
Here are some other, simpler examples from the past. This one is from Weston's Cat Rock Park:
Here is another from Concord's Willow Guzzle Conservation Land:
Here is another from somewhere, I cannot remember where.
Maybe somwbody could weigh in on the significance of this particular pattern. It is quite well defined: a number of rocks in a semicircle with one (or maybe two) rocks in the center and sticking out to the side of the un-finished side of the circle; the whole thing usually less than a foot and a half across.