Affective gestures pointing to things near either in time or space should be made with the hand not very far from the body of the person pointing; and if these things are distant, the hand of the painter should be more extended and the face turned toward the person to whom he is addressing the demonstration.

Nature is so delightful and abundant in its variations that among trees of the same kind there would not be found one which nearly resembles another, and not only the plants as a whole, but among their branches, leaves, and fruit, will not be found one which is precisely like another.

A clever man without wisdom is like a beautiful flower without fragrance.

Water is the driving force of all nature.

I have offended God and mankind because my work didn't reach the quality it should have.

A bird is an instrument working according to mathematical law, which instrument it is within the capacity of man to reproduce with all its movements.

The human foot is a masterpiece of engineering and a work of art.