Prepared piano

A piano with objects inserted between the strings or placed on the strings. That can be bolts, screws, pieces of card-board, leather, felt. In consequence, the sound of the instrument is altered. The prepared piano was introduced by John Cage and used in his compositions ant the beginning of 1940s. Later, the prepared piano was used by many other composers from Europe and the USA, including Kazimierz Serocki and Arvo Pärt.