The desire to know is natural to good men.

Avoid studies of which the result dies with the worker.

Make your faces so that they do not all have the same expression, as one sees with most painters, but give them different expression, according to age, complexion, and good or bad character.

He who walks straight rarely falls.

Why are the bones of great fishes, and oysters and corals and various other shells and sea-snails, found on the high tops of mountains that border the sea, in the same way in which they are found in the depths of the sea?

Of several bodies, all equally large and equally distant, that which is most brightly illuminated will appear to the eye nearest and largest.

Painting is concerned with the ten things you can see: these are darkness and brightness, substance and color, form and place, remoteness and nearness, movement and rest.