Vitruvius Quotes
The difference between "machines" and "engines" is obviously this, that machines need more workmen and greater power to make them take effect, as for instance ballistae and the beams of presses. Engines, on the other hand, accomplish their purpose at the intelligent touch of a single workman...
Vitruvius. Vitruvius: The Ten Books on Architecture. Translated by Morris Hicky Morgan, Harvard University Press, 1914, p. 283.
Marcus Vitruvius Pollio (/vɪˈtruːviəs ˈpɒlioʊ/; c. 80–70 BC – after c. 15 BC), commonly known as Vitruvius, was a Roman author, architect, and civil and military engineer during the 1st century BC, known for his multi-volume work entitled De architectura. He originated the idea that all buildings should have three attributes: firmitas, utilitas, and venustas ("strength", "utility", and "beauty"). These principles were later widely adopted in Roman architecture. His discussion of perfect proportion in architecture and the human body led to the famous Renaissance drawing of the Vitruvian Man by Leonardo da Vinci.