Is the article (a) in the last line the correct one? I'm refering to a specific mattress but mentioning it for the first time.

Question

Staring at the

Orange peel heavens,

Resentment-soaked,

From a floor mattress.

Answer 1

I believe 'a' is the correct article here! You could, of course, say "From the floor mattress" if you wanted to add specificity, but readers can still infer that you're referencing a specific mattress--especially since you're just mentioning it for the first time here; it just seems that you're describing it generally, as a nondescript mattress on the floor of whoever the subject of this poem is.