Final answer:
The student's question appears to miss a) reference the correct poem for line 11, as the provided excerpts do not include Sonnet 29. For a proper analysis, the actual line from Sonnet 29 would be needed.
Step-by-step explanation:
The student's query relates to the redefinition of heaven in Sonnet 29. However, there seems to be an error as the allusion to line 11 likely refers to another poem, not Sonnet 18 or the other excerpts provided. To accurately address the question, it would be necessary to have the correct text from Sonnet 29. A simile in Shakespeare's sonnets typically serves to draw a comparison that highlights and enhances the qualities of the poem's subject. When Shakespeare employs simile to define heaven, he might compare it to something of exquisite beauty or great joy, thus providing a different perspective or emotional nuance to the idea of heaven.