Leonardo da Vinci — "The greatest good is that which is chosen in preference to all others."

"Iron rusts from disuse; stagnant water loses its purity and in cold weather becomes frozen; even so does inaction sap the vigor of the mind."

"Every action needs to be prompted by a motive."

"The painter who draws merely by practice and by eye, without any reason, is like a mirror which copies everything placed in front of it without understanding."

"The eye, which is called the window of the soul, is the principal means by which the understanding can most completely and abundantly appreciate the infinite works of nature."

"Where there is shouting, there is no true knowledge."