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.
Those carvings are variations on a dominant theme:
http://www.knowth.com/newgrange-chamber.htm
The ancient Irish believed that the Sidhe aka the fairies [oops...The Good Folk...Salamander crosses herself and hopes they weren't offended] made them.
Whomever made them got sure around.
The spiral "maze" and variations of it are found everywhere on the planet.
Could have been a universal/archetypal symbol.
Google "The Five Invasions of Ireland" for a wild mythopaeic ride.