Does anyone know what it is? There are about 5 bunched at the end of the trail near Soapstone.

It's not a trail marker. They're too close together and don't look like any of the other markers I've seen on other Reston trails.

I did a Google image search with it, and it found nothing. Thought it might have been a character from Hebrew/Cyrillic/Arabic script. I even thought it might have been a letter from the fictional Star Trek language, Klingon.

Any other ideas?
Attachments:

They're actually Reston Association property markers. That weird symbol is supposed to be an "R" (as in Reston).

Which trail are you referring to? Near Hunter Mill, near 7-11, near golf course?

Near 7-11.

I've seen similar concrete markers that haven't been painted that look really new, too. Those are on the side of the trail nearest South Lakes Drive...

The new ones are plastic and say RA. Not so classy.

When I was little I thought they were meant to mark a horse trail, and that they were sort of a warning to watch where you were stepping.

(I thought part of a horse was depicted).