A Croatian inventor with numerous inventions that are still used today. He is best known for the mechanical pen, the “Penkala,” which is still used for writing. He also invented colored graphite leads.

His list of inventions includes laundry detergent, the thermos bottle, the hot water bottle, a pocket flashlight, insecticide, railway track impregnation, a hovercraft-like flying vehicle, a manometer, a dynamometer, wagon brakes, ebonite material for phonograph records, and a permanent phonograph needle. For his daughter, who did not want to brush her teeth, he invented a rotating toothbrush. He also produced airplanes with a simple control system, which he patented in 1909.