Probably done by the same fellows that have done the crop circles while getting sh8t face drunk.
About a few weeks ago.
First translated phrase turned out to be: "For a good time, call XXXXX"
Next was, "Anybody that wants a XXXX, meet me here Thursday at 9 p.m."
They're working on one, it's a little difficult but it looks like it starts with, "Here I sit ..."
Odds are those crop circle guys are direct descendants of the rock carvers.
For a moment there, I thought that rock thingie was the carving on the side of MY oxcart.