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.

The first of all simple colours is White ... We shall set down White for the representative of light, without which no colour can be seen; Yellow for the earth; Green for water; Blue for air; Red for fire; and Black for total darkness.

Being willing is not enough. We must do.

Anyone who conducts an argument by appealing to authority is not using his intelligence; he is just using his memory.

Learning acquired in youth arrests the evil of old age.

To be a winner you must want to win but must know of the chance of losing and must not fear of it.

I roamed the countryside searching for answers to things I did not understand. Why shells existed on the tops of mountains. How the various circles of water form around the spot which has been struck by a stone, and why a bird sustains itself in the air.