For the most part, Poe wrote “A Dream Within a Dream” using rhyming couplets. However, he also departs from a strict couplet rhyme scheme at strategic moments. Whereas couplets conventionally communicate a formal sense of order and balance, in this poem, Poe disrupts the couplet scheme to create a subtle effect of disorder and imbalance. His strategy is simple but effective. At one point in each of the poem’s two stanzas, he inserts a third rhyme to create a triplet. The first insertion appears right away in the opening three lines:

     Take this kiss upon the brow!
     And, in parting from you now,
     Thus much let me avow.

These lines set up an initial expectation for triplets, which the following lines immediately thwart. The poem features a strict use of couplets for the rest of the first stanza, establishing a new expectation, this time for couplets. The poem satisfies this expectation for many lines. But then, in the middle of the second stanza, another triplet throws the pattern off:

     How few! yet how they creep
     Through my fingers to the deep,
     While I weep—while I weep!

This second triplet (lines 16–18) appears at a moment of heightened emotional intensity, disrupting the couplet scheme when the speaker is losing all sense of mental balance. It’s in this way that Poe uses rhyme as a subtly disordering force.