Conversation so far:
Was John Cage's style of composition different than composers before him?
John Cage's work from the sixties features some of his largest and most ambitious, not to mention socially utopian pieces, reflecting the mood of the era.
In what way were John Cage's work from the sixties ambitious?
HPSCHD (1969) was a gargantuan and long-running multimedia work John Cage made in collaboration with Lejaren Hiller.
What was the rhythmic structure of these pieces?
Soon after John Cage started writing percussion music and music for modern dance, he started using a technique that placed the rhythmic structure of the piece into the foreground.
Was John Cage's technique that placed the rhythmic structure of the piece into the foreground well-received?
What are some other features of the percussion music John Cage wrote besides using a technique that placed the rhythmic structure of the piece into the foreground?
In John Cage's Imaginary Landscape No. 1 (1939) there are four large sections of 16, 17, 18, and 19 bars, and each section is divided into four subsections.
Did John Cage have any reasoning behind why he chose the percussion technique that placed the rhythmic structure of the piece into the foreground?

Question: What are some of his new approaches to harmony?
Self-contained rewrite: What are some of John Cage's new approaches to harmony?