Make yourself a master of perspective, then acquire perfect knowledge of the proportions of men and other animals.
Leonardo da VinciIf you are alone you belong entirely to yourself. If you are accompanied by even one companion you belong only half to yourself or even less in proportion to the thoughtlessness of his conduct and if you have more than one companion you will fall more deeply into the same plight.
Leonardo da VinciPerspective is a most subtle discovery in mathematical studies, for by means of lines it causes to appear distant that which is near, and large that which is small.
Leonardo da Vinci