In the twentieth century, composers tried to break new ground in music by writing in different and increasingly unusual ways. Possibly no one in the history of music has written more unusual pieces than the German Karlheinz Stockhausen.

 

He has worked with the twelve-tone technique created by Arnold Shoenberg, and also used electronic devices and instruments in his scores to create sounds that ordinary instruments cannot.

 

In perhaps his most dramatic piece - Helikopter Streichquartett - the four members of a string quartet each perform from a separate helicopter circling above the concert hall, and the sound of their performance is broadcast to the audience, along with the sound of the helicopters.