The sonic pattern that is most prominent in the poem is the rhythm. The Purdue University Online Writing Lab describes rhythm as "a major aspect of sound in more formal verse." Rhythm tends to dictate the audio layout of the poem. Read aloud, a poem may seem to have a beat that the verses follow. This is the rhythm.
The rhyme scheme is the pattern that rhythm takes in a poem. Poets use it to make love poem flow freely and smoothly. They also place rhyme schemes in free verse to make a more jilted sort of poem that seems less natural. Rhyme is a sonic pattern that can have visual meaning, when the rhyming words are read differently aloud than they look on paper. Syllable stress is another aspect of rhyme scheme that helps poets project meaning.
Poetry often relies on sonic patterns created through repetition. Alliteration is like a rhyme. It is performed by repeating the same sound over and over again. It is similar to assonance, which is the repetition of a vowel sound. These and other literary device are used to stress certain ideas in a poem or to build a refrain. A refrain is a repetitive portion of the poem that separates the verses while signifying a change in tone, emotion or idea. Repetition in poetry also creates cadence, a song-like quality of poems.
Some poets go for a more direct approach at creating sonic patterns in their poems. Onomatopoeic words are those that resemble the sounds they are describing. Classic examples are "boom," "bang" and "zap." Onomatopoeic patterns are a more direct approach to conveying sounds in poetry.