A Gamelan is not a single instrument, but a traditional ensemble from Indonesia, primarily the islands of Java and Bali. It consists mostly of percussive instruments, including tuned gongs, metallophones (known as saron or gender), and drums (kendang). Some ensembles also include bamboo flutes and stringed instruments. The instruments are typically forged from bronze or iron and are housed in elaborately carved wooden frames. One of the most fascinating aspects of a Gamelan is that the entire set is tuned to itself; you cannot swap an instrument from one Gamelan into another because they will not be in tune. The tuning systems, 'slendro' (five notes) and 'pelog' (seven notes), differ significantly from Western equal temperament. Gamelan music is communal, often accompanying shadow puppet plays (wayang kulit) or sacred dances, and it heavily influenced Western composers like Claude Debussy after he heard it at the 1889 Paris Exposition.