Aha—I think I’ve started to suss the basis of poets like JH Prynne and Keston Sutherland—I’m thinking Charles Ives. He composed pieces inspired from his childhood. His father had a music shop; the child heard different instruments played concurrently, not in conversation, not in competition, merely in coincidence.
Obviously, in poetry, you cannot have one person speaking two voices at the same time, but you can snatch part phrases, mix and match. Whether this is how the poems are actually built, I’ve no idea, but it does give me a handle to start investigating the form.