Paterson structures the poem as nine quatrains with a strict rhyme scheme and rhythm.
Apart from a few slant rhymes he uses a tight AABB rhyme throughout.
Perhaps the combination of full rhymes and half rhymes relates to the theme of perfection and imperfection that permeates the poem. The rhythm is for the most part iambic tetrameter, similar to that used by Donne in A Valediction: Forbidding Mourning.
This gives the poem a set frame within which Paterson explores philosophical ideas; it could imply that no matter what we think or how much effort we put into influencing the course "our arrows" take, we are still held within the confines of fate’s design.
In the first four stanzas, Paterson describes his son drawing as an outside observer.
In stanza five with the pivotal use of "But", the poem shifts from describing Jamie's personal experience to addressing the boy directly. Paterson moves from talking about his son to addressing a more universal concern in terms of how we all deal with what we are given.
Overall, the poem's structure also has a 'circular' feel to it, as it begins with the boy's poorly drawn circle and ends with the "perfect ring", which gives it a sense of completion.