Of the horse I will say nothing because I know the times. - Leonardo da Vinci

"There are three classes of people: those who see. Those who see when they are shown. Those who do not see."

Time stays long enough for anyone who will use it.

Poor is the pupil who does not surpass his master

Simplicity is the ultimate sophistication.

Nature is the source of all true knowledge. She has her own logic, her own laws, she has no effect without cause nor invention without necessity

Nature is full of infinite causes that have never occurred in experience.

Thou, O God, sellest us all benefits, at the cost of our toil....