Poetry is a form of literary art that uses aesthetic and often rhythmic qualities of language to evoke meanings in addition to, or in place of, literal or surface-level meanings. Any particular instance of poetry is called a poem and is written by a poet. Poets use a variety of techniques called poetic devices, such as assonance, alliteration, euphony and cacophony, onomatopoeia, rhythm, and sound symbolism, to produce musical or incantatory effects. Most poems are formatted in verse: a series or stack of lines on a page, which follow a rhythmic or other deliberate pattern. For this reason, verse has also become a synonym for poetry.