This is a an ancient sundial. To use it, one puts a stick through the hole at the top of the stone, and the shadow cast upon the circle below would give a measurement. There is, of course, just one little problem, as this picture demonstrates. What do you do when the sun doesn't shine ?

This is a an ancient sundial. To use it, one puts a stick through the hole at the top of the stone, and the shadow cast upon the circle below would give a measurement. There is, of course, just one little problem, as this picture demonstrates. What do you do when the sun doesn't shine ?