Comment by jbmilgrom
I don’t think that’s the right take. Poetry manipulates common grammatical rules and still communicates meaning from the writer to the reader, perhaps in an even deeper way because of that manipulation. Of course in Java and many other programming languages, grammatical errors will simply not compile. LISP is one of those few languages where grammar can change from program to program, much like with poetry
Even though there is much more freedom in poetry, it is still defined by a specific set of rules/features: verses, rhythm, stanzas, spacing, meter, and rhyming. It's only because of these restrictions that it is so obvious when writing is or isn't poetry. These features and forms can streched, but unlike lisp they cannot be completely redefined.