Who poverty and tatters and hollow-eyed and high sat up smoking in the supernatural darkness of cold-water flats floating across the tops of cities contemplating jazz,

from Allen Ginsberg – Howl on Rap Genius

Meaning

These lines depicts the “best minds” sitting in an NYC flat (the poem is mostly set in and around New York, where Ginsberg and his friends lived), getting high and thinking/talking about music. Jazz, to be precise. To cope with poverty, all they had was the best kush and the best beats.

Here’s an early ‘50s recording of Charlie Parker and Dizzy Gillespie, the height of cool in jazz at the time:
https://www.youtube.com/watch?v=Clp9AeBdgL0

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