Helmut Lachenmann: “Guero” (1969)
Lachenmann’s “Guero” is a fascinating piece of notation, calling for playing the innards of the piano. It sits in stark contrast to most of his Klaviermusik collection, which is largely atonal and unpredictable, albeit traditionally performed, piano music.
Portland-via-Chicago producer Warmdesk used Lachenmann’s piece as inspiration for his fantastic techno and tech house Guero Variations album ten years ago on Deluxe Records. (I also incidentally designed its cover and helped out on a track.)