The pattern in which the rhymed line‐endings are arranged in a poem or stanza. This may be expressed as a sequence of recurrences in which each line ending on the same rhyme is given the same alphabetic symbol: thus the rhyme scheme of a limerick is given the notation aabba. Rhyme schemes may follow a fixed pattern, as in the sonnet and several other forms, or they may be arranged freely according to the poet's requirements. The simplest rhyme schemes are those of rhyming couplets (aabbcc, etc.) and of the common quatrain forms (abab, abcb, abba), while those of ottava rima, rhyme royal, the Spenserian stanza, and the French fixed forms are far more intricate.