The meter of Shakespeare's sonnets is iambic pentameter (except in Sonnet 145).
The only exceptions are Sonnets 99, 126, and 145. Number 99 has fifteen lines. Number 126 consists of six couplets, and two blank lines marked with italic brackets; 145 is in iambic tetrameters, not pentameters.
Often, the beginning of the third quatrain marks the volta ("turn"), or the line in which the mood of the poem shifts, and the poet expresses a revelation or epiphany.
In Shakespeare's sonnets, however, the volta usually comes in the couplet, and usually summarizes the theme of the poem or introduces a fresh new look at the theme. each line containing ten syllables
This scheme interlaces a rhyming pair of couplets to make a quatrain, then builds the whole sonnet of three differently rhymed quatrains and a concluding couplet
The Shakespearean sonnet affords two additional rhyme endings (a-g, 7 in all) so that each rhyme is heard only once. This not only enlarges the range of rhyme sounds and words the poet can use, it allows the poet to combine the sonnet lines in rhetorically more complex ways. Shakespeare often gave special emphasis to the break between the second and third quatrains (equivalent to the major break between the 8 quatrain lines and the 6 tercet lines in the Italian sonnet), but he also paired and contrasted the quatrains in many other ways, creating a great range of argumentative or dramatic effects.
Shakespeare invested the couplet with special significance. It often summarizes or characterizes the musings of the three quatrains in a sardonic, detached or aphoristic voice, standing in some way aloof from the more turbulent and heartfelt outpouring of the quatrains.
In the sonnets Shakespeare transforms the literary stereotypes of the