Early April sunrise shadow. At this time of year the shadows cast by Fan Llia and Maen Llia meet at Datum stone 1, as indicated by this alignment megalithic.co.uk/modules.php?op=modload&name=a312&file=index&do=showpic&pid=209954.
When viewed from this direction fan Llia’s shadow crawls down the eastern flank of Fan Nedd at a snails pace (the hill beyond the shadow here) towards Datum 1. When the shadow meets the flatter level of the platform it disappears in seconds, leaving the full shadow of Maen Llia in its wake, as though it had appeared out of thin air.
This is an optical illusion that has to be seen to be believed.
Image credit: cerrig