Figured I'd follow up here, many months later.
I've absorbed as much as I can on this subject and still haven't quite found the information I'm looking for.
But I did have a strange experience this week which pointed back to Buddhism.
To keep it short - there's a place where I've been hiking regularly for nearly 20 years. And there is an unremarkable section of a trail where I've always felt a strange vibe. There is a particular tree on this section of trail where I once saw a person standing, but when I came up to the tree the person was no longer there. There have been several other strange things like this at this tree, and on Tuesday I stopped at the tree and began examining it. When I walked around to the back of the tree I found a 2" clay Buddhist face (picture below). It looks like it has been there a number of years, judging by the way the bark has grown around it.
Does anyone have any info on this symbol?