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
Syllabic verse perceived as (usually) 3-stress lines. Syllabic poetry can also take a stanzaic form, as in Marianne Moore's poem "No Swan So Fine", in which the corresponding lines of each stanza have the same number of syllables. This poem comprises 2 stanzas, each with lines of 7, 8, 6, 8, 8, 5, and 9 syllables respectively. The indented lines rhyme. As in accentual-syllabic verse, there is some flexibility in how one counts syllables. For example, syllables with y- or w-glides may count as one or two syllables depending on the poet's preference. Moore counts "Dahlias" (a y-glide) as 2 syllables, and