He refers to this point as the "hinge" of the line. In the "ruba'i" the rhythm after the "hinge" can be either – u or u –. The same choice is sometimes found in early poets in the metre 3.4.7(2) in the same way after the break:  In metres where a line ends with the sequence u u –, as in the above "ruba'i" metre, the two short syllables are often replaced with a single long syllable. This replacement is also found in the first half of the line, but much less commonly. In a sample of 200 lines taken from the "ruba'i" metres, Elwell-Sutton found that the final u u – became – – in 50% of lines, the first u u – became – – in 5% of lines, and for the middle u u – there were no examples. When the rhythm u u – is replaced by – – in the first half of the line, there is usually a phrase boundary or potential pause after the second long syllable. The following line from a "ruba'i" is typical:  The "biceps" ending – u u – is also sometimes found in Arabic poetry, in the basīṭ metre, for example in poems written by the poet Abu Nuwas, who was of half-Persian origin. Persian poems always use rhyme, and from the point of view of rhyme can be classified into various types:       Persian rhymes often consist of a single syllable, for example "māh / siyāh"; but there are also plenty of instances of longer rhymes, such "sāzande / navāzande" or "pūyandagān / gūyandagān". Following the actual rhyming word there may be a "radīf", which is a word or series of words that is repeated after every rhyme, for example "šekāyat mīkonad / hekāyat mīkonad" (Rumi). As well as the main rhyme, there may also be additional internal rhymes in a verse. Persian rhyme sometimes provides evidence of an earlier pronunciation of the language. For example, in Saadi's poem "Cloud and wind" quoted below, the word "naxorī" rhymes with "nabarī", presumably because in Saadi's day, at least in poetry, the first word was pronounced "naxwarī".