In Shakespearian Sonnet 20, how does each quatrain connect to convey the meaning of the entire poem?

William Shakespeare’s Sonnet 20 is a love poem in which the gender of the subject, who the speaker addresses, is ambiguous. The speaker has been assumed to be male. The sonnet includes numerous comparisons between the speaker’s beloved and a woman or women. This poem has most often been interpreted as indicating that the beloved is a man who has many female characteristics or actually resembles a woman. By extension, the speaker’s love for this person has been interpreted as either platonic or sexual in nature.
The first quatrain (lines 1–4) makes several parallel comparisons between the subject and a woman or women and appears to mix up the gendered qualities of the subject. The speaker addresses the subject as “the master mistress” of his passion. The direct positive comparisons the speaker draws are to the “face” and “gentle heart” of a woman. Another positive attribute is that the subject lacks “false women’s fashion,” or fickleness.
The second quatrain (lines 5–8) includes further comparisons, referring to “An eye more bright.” The speaker then refers to the beloved's effects on others, as their bright gaze gilds the person it falls on, and indicates that the subject is male or masculine: “A man in hue.”
The third quatrain (lines 9–12) emphasizes the femaleness of the subject, whom the speaker says was “first created” to be a woman. The sonnet has a shift in line 10, when the speaker claims that Nature, because she doted on the subject, added “one thing” to the originally female person. While that is “nothing” to him, it did defeat him. One interpretation is that these lines emphasize the speaker’s constancy. A different suggestion, however, is supported by the final couplet (lines 13–14). The word “prick’d” in line 13, along with the reference to “women’s pleasure,” is often believed to indicate that the thing referenced is the subject’s penis. This interpretation emphasizes the sexual nature of the speaker’s love.