Gruppen

"Gruppen", a Karlheinz Stockhausen 's piece for 3 orchestras created in 1958 in Köln....

A large orchestra of 109 players is divided into three orchestral units, each with its own conductor, which are deployed in a horseshoe shape to the left, front, and right of the audience. 

"...in Gruppen … whole envelopes of rhythmic blocks are exact lines of mountains that I saw in Paspels in Switzerland right in front of my little window. Many of the time spectra, which are represented by superimpositions of different rhythmic layers—of different speeds in each layer—their envelope which describes the increase and decrease of the number of layers, their shape, so to speak, the shape of the time field, are the curves of the mountain's contour which I saw when I looked out the window..."  K.S. ( Cott 1973, 141)

here, an amazing interpretation in the "Cresc...Biennale für Moderne Musik", conducted by Matthias Pintscher, Lucas Vis & Paul Fitzsimo.