Cage liked to use sounds created with prepared instruments (a piano with nuts and bolts thrown onto the piano strings) or household items (jugs of water, radios).
John Cage has an extremely unusual and challenging conception of what music could be and how it relates to sound in general.
He often encouraged audiences to concentrate on very disciplined sequences of improvised sound using odd objects (the plucking of cacti needles), and on background noises that were specific to a live performance space (traffic, air conditioning, coughing).
In later works, Cage stripped the idea of sound down to the bare minimum, scoring performances that simply incorporated the sound of people getting on with daily tasks (writing, washing up, tending houseplants).
“Ultimately,” says Cage, “a music could be made… in which all you would do for musical pleasure would be to make audible the sounds that are already in existence.”