Ruba'i

In classical Persian poetry, the ruba'i is written as a four-line (or two-couplet / two-distich) poem, with a rhyme-scheme AABA or AAAA.

As variations of this scheme, any sequence of – u, except the final syllable of each line, can be replaced by a single "overlong" syllable, such as gēkh, tīf, luṭf in the poem above, containing either a long vowel followed by a consonant other than "n", or a short vowel followed by two consonants.

Another variation, as a poetic licence rule, is that occasionally a sequence of two short syllables (u u) can be replaced by a single long one (–).

A third variation is to use the same metre as above, but with the sixth and seventh syllables reversed: The verse form AABA as used in English verse is known as the Rubaiyat Quatrain due to its use by Edward FitzGerald in his famous 1859 translation, Rubaiyat of Omar Khayyam.

Algernon Charles Swinburne, one of the first admirers of FitzGerald's translation of Khayyam's medieval Persian verses, was the first to imitate the stanza form, which subsequently became popular and was used widely, as in the case of Robert Frost's 1922 poem "Stopping by Woods on a Snowy Evening".