The performance of the analog computer was impressive. A stadimeter is a type of analog computer. It is considered an early example of a paper analog computer. Any physical process that models some computation can be interpreted as an analog computer. He discovered the topological gain formula while investigating the functional operation of an analog computer. Separate sync is most common with VGA, used worldwide for analog computer monitors. Analog computer designs were published in electronics magazines. During the Middle Ages, several European philosophers made attempts to produce analog computer devices. In some analog computer designs, multiplication is much preferred to division. The Antikythera mechanism is believed to be an early mechanical analog computer. The Antikythera mechanism is believed to be the earliest known mechanical analog computer. The Simulation Council (or Simulations Council) was an association of analog computer users in US. In 2010, it was replaced with a restored Donner Model 3400 analog computer. Project Typhoon was an analog computer developed by RCA in 1952. The sights were coordinated by a sophisticated analog computer system developed by Sperry Gyroscope Company.