Why, you may ask, is this stone leaning at such an angle? Well, it wasn’t placed here carefully, it was actually thrown from the top of nearby Pen y Gaer (a hillfort). A giant was up there, and he’d left his flock of sheep in the protection of his sheepdog. However, the dog had sneaked into the protection of a nearby cromlech (Cwt y Bugail) for a crafty nap – so the missile was thrown in an attempt to wake him up and put him back on the job.
(from Chris Barber’s More Mysterious Wales)