Formalism in its way sets free

It isn't simply that the rhythm and rhyme
Give each line motion and constrict the sense,
But that the poem, shaped in its own time,
Permits communication lacking pretence;
With rhyme and metre, shaped into a form,
The ideas and the meanings will agree,
Though this is by no means the only norm
For verse that carries meaning can be free.
Still each of us, with prosody that flies
Across the page and gives our words their wings,
Commits entirely to raise to the skies
The words that signify and voice that sings,
So that, like Shakespeare, we at last confirm
The medium is the message, in its term.