Silent film legend Buster Keaton was a technical pioneer. In his short film 'The Play House,' he used a custom-made camera shutter to film himself playing every single member of a nine-piece orchestra. This included Keaton playing the cello, the drums, and the clarinet all on the same screen. To achieve this without the benefit of modern computers, the film had to be rewound nine times, and the lens was masked with perfect precision for each pass. This meant Keaton had to keep a perfect internal rhythm (an 'internal instrument') to ensure all nine versions of himself stayed in sync. It remains one of the most complex technical achievements of the silent era. The sequence showcased not just his comedic legend, but his deep understanding of film as a mechanical and rhythmic instrument.