Although nature commences with reason and ends in experience it is necessary for us to do the opposite, that is to commence with experience and from … - Leonardo da Vinci

I myself have proved it to be of no small use, when in bed in the dark, to recall in fancy the external details of forms previously studied, or other noteworthy things conceived by subtle speculation; and this is certainly an admirable exercise, and useful for impressing things on the memory.

It had long since come to my attention that people of accomplishment rarely sat back and let things happen to them. They went out and happened to things.

Light is the chaser away of darkness. Shade is the obstruction of light. Primary light is that which falls on objects and causes light and shade. And derived lights are those portions of a body which are illuminated by the primary light. A primary shadow is that side of a body on which the light cannot fall.