Dimmi, dimmi se mai fu fatta cosa alcuna - Leonardo da Vinci

The knowledge of past times and of the places on the earth is both an ornament and nutriment to the human mind.

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 now and then go away, have a little relaxation, for when you come back to your work your judgment will be surer. Go some distance away because then the work appears smaller and more of it can be taken in at a glance and a lack of harmony and proportion is more readily seen.