In poetry, a rhyme scheme refers to the pattern created by the repetition of sounds (rhyme) in different verses of a poem and that is marked by letters that indicate the lines that rhyme, for example in a poem of four verses with an abab rhyme scheme the rhyme occurs as the first and third verse (marked with letter "a") rhyme and the second and fourth verse (marked with letter "b" rhyme). Additionally, the rhyme scheme varies according to the number of verses and the features of the poem itself. In the case of an octave, this is a type of poem that contains eight verses and each of this verses is composed by fives sets of iambs (a combination of one unstressed and one stressed syllable). In terms of rhyme, the rhyme in octaves is between the first, fourth, fifth and eight verse and between the second third, sixth and seventh verse or "abba abba" rhyme scheme. Thus, it can be concluded the rhyme scheme of an octave is "abba abba".
