Samuel Beckett (1906-1989)
Technically this isn’t a poem, but an extract from Beckett’s novel Watt, where it’s set out as continuous prose. But it’s too much fun to read to leave out on the grounds that it’s not ‘a poem’.
If you want to tie your head in knots you can try to define ‘poetry’ and ‘poem’. Whatever your definition there will always be a liminal case that challenges the definition. Beckett’s prose is also often a lot funnier than the stern photos of Beckett would lead you to expect. So go along for the ride. And enjoy.