Read the passage. The Ornithopter Many people know Leonardo da Vinci today as an artist, and it is true that he was indeed a great painter and sculptor, but he was also an inventor and one of the first individuals in recorded history to draft detailed plans for a flying machine. In order to make a living, Leonardo often depended upon wealthy individuals who would commission work from him. That means they would hire him and pay him to create specific work they wanted. In 1482, when he was 30 years old, Leonardo heard of an opportunity to work for Ludovico Sforza, the Duke of Milan. The duke, however, did not want a painter; he wanted a military engineer to help him defend the city against its enemies. This was an excellent opportunity that would pay Leonardo well, but Leonardo was a peaceful man. He considered war to be "a beastly madness." He preferred to make things of beauty. Leonardo made the decision that he could tolerate making weapons if the resources the duke could provide would also allow him to create things he loved. He sent a letter to the duke detailing his skills in designing and building weapons. "I will assemble catapults, mangonels, trebuchets and other instruments of wonderful efficiency…I will make an infinite number of items for attack and defense," he wrote. Leonardo’s letter convinced the duke of his talents, and he got the job. He set about designing the weapons that the duke desired. But Leonardo was infinitely creative, always thinking of new things, new ideas—he could not be limited to weapons alone. One idea that he had not mentioned in his application was the ornithopter. It was not a weapon of war, and it was not something that the duke had asked for, but Leonardo went ahead and designed it anyway. Leonardo was fascinated by the idea of flight. The word "ornithopter" comes from two words meaning "bird" and "wings." And on first inspection, his plans resembled a bird’s wings attached to a human being’s arms. He concluded that a human being’s arms were neither strong enough nor li