When the thing taken into union is perfectly adapted to that which receives it, the result is delight and pleasure and satisfaction.
Leonardo da VinciThe variety of colour in objects cannot be discerned at a great distance, excepting in those parts which are directly lighted up by the solar rays.
Leonardo da VinciThose who are in love with practice without knowledge are like the sailor who gets into a ship without rudder or compass and who never can be certain whether he is going. Practice must always be founded on sound theory, and to this Perspective is the guide and the gateway; and without this nothing can be done well in the matter of drawing.
Leonardo da Vinci