In the aptly named "Backwards," Shire makes the unique choice to write a poem that reverses its lines in its second half. This type of poetry is referred to as mirror poetry, or palindrome poetry, as it literally mirrors itself in structure. In this particular poem, the choice allows Shire to replay the events shown in the first half, shedding new light on them in their new order. While this is not a commonly used poetic technique, there are a few other examples of it that demonstrate what it can add to a work.
Writer Julia Copus writes with this mirror technique in her poem "The Back Seat of My Mother's Car":
You were mouthing something I still remember, the noiseless words
piercing me like that catgut shriek that flew up, furious as a sunset
pouring itself out against the sky. The ensuing silence
was the one clear thing I could decipher –
the roar of the engine drowning your voice,
with the cool slick glass between us.
With the cool slick glass between us,
the roar of the engine drowning, your voice
was the one clear thing I could decipher –
pouring itself out against the sky, the ensuing silence
piercing me like that catgut shriek that flew up, furious as a sunset.
You were mouthing something: I still remember the noiseless words,
In this excerpt, Copus recounts being separated from her father. Like the moments in "Backwards," the memory depicted in this scene has pinpoint clarity, as the speaker is able to recall the color of the sunset and the feel of the car window's glass. She uses mirroring the text in order to capture the feeling of two figures receding away from each other in the distance, highlighting it as suitably heart-rending.
Another example of this form is the poem "Myth" by Natasha Trethewey:
you back into morning. Sleep-heavy, turning,
my eyes open, I find you do not follow.
Again and again, this constant forsaking.*
Again and again, this constant forsaking:
my eyes open, I find you do not follow.
You back into morning, sleep-heavy, turning.
Trethewey depicts the tragedy of Orpheus and Eurydice, in which Orpheus tries to rescue Eurydice from the underworld. He fails to do so because he cannot help but turn around and look at her, which breaks the agreement he had with Hades. In using a reversed structure here, Trethewey is able to paint the endlessly circular nature of Orpheus's grief, as he replays this terrible moment over and over.
Trethewey and Copus's work resembles Shire's in these examples, as they use this mirrored structure to show the way in which a memory is haunting. Just as Shire's speaker is working through a painful past, their speakers find themselves unable to stop looping these difficult moments. The mirror structure is a useful one for showing the way in which time can pass, but a memory will linger, as the reader is required to walk back through the scenes they've just read.