The Da Vinci Notebooks
Any shadow cast by a body in light and shade is of the same nature and character as that which is inseparable from the body. The centre of the length of a shadow always corresponds to that of the luminous body 72 . It is inevitable that every shadow must have its centre in a line with the centre of the light.
On the shape of derived shadows (166-174).
94:72 6: This second statement of the same idea as in the former sentence, but in different words, does not, in the original, come next to the foregoing; sections 172 and 127 are placed between them.