They first appeared in the 1900s when they were actuated either mechanically or pneumatically. In 1908 Alfredo Barrachini in Rome had added electric lights inside the arms that turned on as they extended but operation was still by a cable system. Electric operation came in 1918 when the Naillik Motor Signal Company of Boston added electric motor drive. This system was superseded by two French inventors, Gustave Deneef and Maurice Boisson, who used a linear solenoid in 1923. The final complete system came in 1927 when Berlin-based Max Ruhl and Ernst Neuman combined internal illumination and solenoid operation.