OF LIGHT AND SHADOW IN A TOWN.
When the sun is in the East and the eye is above the centre of a town, the eye will see the Southern part of the town with its roofs half in shade and half in light, and the same towards the North; the Eastern side will be all in shadow and the Western will be all in light.
Taken from The Notebooks of Leonardo da Vinci edited by Jean Paul Richter, 1880.