Except that the last time I discussed this I was talking about red and white pairs [Click here], I came across a similar phenomenon at a site in Carlisle, walking with FFC. There are about fify rock piles along a slight slope facing south over a wetland. Besides piles there were some other impressive features:
There were piles with deliberate vertical "fins":
And piles with what looked like deliberate white rocks:
And piles with deliberate black rocks:
Maybe it is a stretch but these features are similar to what I was seeing at that site with the "grammar of brown and white stones" [Click here] and I am inclined to start keeping an eye out for other sites with this kind of deliberate white rocks, black (or brown) rocks , and vertical fins.
Besides piles like that there were also some effigy-like piles.