Sonnet 30 up of fourteen lines in three quatrains and a couplet, rhyming "abab cdcd efef gg". While using the rhyming and metrical structure of the 'English' or 'Surreyan' sonnet, Shakespeare often also reflected the rhetorical form of the Italian form also known as the Petrarchan sonnet. It divides the sonnet into two parts: the "octet" (the first eight lines) usually states and develops the subject, while the "sestet" (the last six lines) winds up to a climax. Thus a change in emphasis, known as the "volta", occurs between the end of the eighth and the beginning of the ninth lines —
Poetry calligraphy. These basic units of poetic form are often combined into larger structures, called "poetic forms" or poetic modes (see following section), as in the sonnet or haiku. Poetry is often separated into lines on a page. These lines may be based on the number of metrical feet, or may emphasize a rhyming pattern at the ends of lines. Lines may serve other functions, particularly where the poem is not written in a formal metrical pattern. Lines can separate, compare or contrast thoughts expressed in different units, or can highlight a change in tone. See the article on line breaks