man named Hero was the best-known maker of the devices. His clockwork designs, driven by heat, pressure, gravity, and magnets, included temple doors that opened only when a fire was lit in front of them, a holy water fountain that flowed when a supplicant dropped a coin into it, an orrery that moved by itself, a trumpet-playing robot, mechanical birds that really sang, and a theater where everything—sets, actors, curtains, and special effects—was automated. Hero also invented a device called an aeolipile, two copper tubes leading up from a sealed container and into a freely rotating sphere.
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