 Furthermore, Middle English poetry also employed the hemistich as a coherent unit of verse, with both the Pearl Poet and Layamon using a regularized set of principles for which metrical (as well as alliterative) forms were allowed in which hemistich position.In Arabic and Persian poetry, a line of verse almost invariably consists of two hemistichs of equal length, forming a couplet.In some kinds of Persian and Arabic poetry, known as mathnawi or masnavi, the two hemistichs of a line rhyme with the scheme "aa", "bb", "cc", "dd", etc.