This is a new one to me, and distinctly weird. Not a great photo, that was taken out of curiosity and intrigue. This grave (at the old Urquhart Cemetery on the Black Isle) has a clear, and very neat circle around it, in the grass. It looks like it has been worn there by some means, and the worn part is narrow. Narrower than you'd expect from say, someone casually walking around it. It also overlaps the adjacent plot.

Perhaps just a regular grieving relative, who's developed some ritual habit? The most recent addition to the plot was in 1991. As I said, it does look weird. I'm glad that I'd cycled well away from the place, before the sun set, and a very full moon started to rise above the horizon!