Sonnet 3 form of a Shakespearean sonnet: fourteen decasyllabic, iambic pentameter lines, that form three quatrains and a concluding rhyming couplet. It follows the form's rhyme scheme: "abab cdcd efef gg". Each line of the first quatrain of Sonnet 3 exhibits a final extrametrical syllable or "feminine ending". The first line additionally exhibits an initial reversal: In this sonnet, the poet is urging the 'fair youth' to preserve something of himself and something of the image he sees in the mirror by fathering a child, "Now is the time that face should form another". The message is reiterated in the last lines
Sonnet 15 that Sonnet 15's closing line "As he [i.e. Time] takes from you, I engraft you new" (15.14) is the "first of several traditional claims for the immortalizing power of verse." This theme of poetic immortality is continued in later sonnets, including sonnet 17's closing couplet "You should live twice: in [your child] and in my rhyme," in sonnet 18's last few lines "Nor shall death brag thou wander'st in his shade / When in eternal lines to time thou grow'st. / So long as men can breathe or eyes can see, / So long lives this, and this gives life