Actually, the iPhone of its day. This is a Curta mechanical calculator developed by Curt Herzstark in Vienna, Austria. It fit easily in the palm of your hand and was able to perform addition, subtraction, multiplication and division. The progeny of Leibniz’s Stepped Reckoner, the Curta used a combination of gears invented by Leibniz along with a crank on the top which moved numbers into the machine and was also used to select which mathematical function to use. Herzstark thou