Ramblers were left puzzled when they noticed these weird shapes cut into the heather beneath Moel Famau.
Some people had thought that aliens had landed, or that a recent dry spell had brought back to the surface the foundations of long forgotten buildings or markings.
But the answer was far less fanciful. Since 2003, rangers for Denbighshire Countryside Service have been cutting the shapes in the heather as part of the service's management of the countryside!
