How does the structure of ars poetica reinforce the poems theme

The lack of traditional structure illustrates MacLeish's idea that a poem shouldn't be confine by rule

The poem's theme is what a poem should be, and it is represented in the structure repeatedly by the use of devices

Explanation:

"Ars Poetica" uses several poetical devices to convey its message, it uses simile, alliteration, paradox, metaphor, and anaphora, this one repeats the expression "A poem should be" which is the main theme of this piece of work. It also has paradoxes and juxtaposition of opposites to explain how a poem should be.