In this paper we introduce an Interactive Virtual Musical Instrument that plays computer generated music notes. The approach taken for implementing the virtual instrument is based on unique marker tracking in the real world using live video feed. The relationship between music pitches and frequencies is discussed and analysed, as well as the complex behaviour that derives from simple models, such as cellular automata. Music notes are generated using both sine waves and cellular automata, and later used as the sounds played by the Interactive Virtual Musical Instrument.