Metre (poetry) of over some two-and-a-half millennia. Beginning with the earlier recorded forms: the Classic of Poetry tends toward couplets of four-character lines, grouped in rhymed quatrains; and, the Chuci follows this to some extent, but moves toward variations in line length. Han Dynasty poetry tended towards the variable line-length forms of the folk ballads and the Music Bureau yuefu. Jian'an poetry, Six Dynasties poetry, and Tang Dynasty poetry tend towards a poetic metre based on fixed-length lines of five, seven, (or, more rarely six) characters/verbal units tended to predominate, generally in couplet/quatrain-based forms, of various total verse lengths. The Song poetry
Poetry recognisable structures or forms, and write in free verse. But poetry remains distinguished from prose by its form; some regard for basic formal structures of poetry will be found in even the best free verse, however much such structures may appear to have been ignored. Similarly, in the best poetry written in classic styles there will be departures from strict form for emphasis or effect. Among major structural elements used in poetry are the line, the stanza or verse paragraph, and larger combinations of stanzas or lines such as cantos. Also sometimes used are broader visual presentations of words and