Both Troilus and Cressida and The Winter's Tale deal with nature as an allegory for human nature. Many kinds of metaphors are used, from the classically romantic, to the dirty joke, to positive and negative portrayals of personalities. Many of the most powerful metaphors are in the initial portion of the play.
In Act I, Scene I, of Troilus and Cressida, Troilus compares being observed by his father and Hector to "as when the sun doth light a storm" (line 31). Presumably his inner turmoil over his love for Cressida is the storm, and his false good humor is the light in the storm. This implies that nature can be false, as well. Later in the same discussion, Troilus says his hopes are drowned, again using the depths of the ocean as an expression of his emotions (line 37). Later he compares Cressida to a pearl of India (line 76), a rare natural phenomenon. Finally, the distance between he and Cressida is a "wild and wandering flood," (line 78). With the exception of the description of the worth of Cressida, most of these are negative descriptions using Nature.
Act I, Scene II has many depictions of Nature. Alexander says that "every flower Did, as a prophet, weep what it foresaw" (lines 13-14). Alexander sees Nature as omniscient. At this part of the play, prophecy is foreshadowing. Next, Alexander compares Ajax to beasts, which are a part of Nature. Then he directly references Nature, saying that he is so full of "humours" that he is unwise, yet able to see men's true characters (line 20). Later, Pandarus and Cressida use the rhythms of Nature as something reliable on which to swear (lines 110-111). This is a very different view of Nature from Troilus's, as one that is powerful, all knowing, and reliable.
In the next scene, Agamemnon uses Nature as metaphor, saying that the veins of important plans are the location of problems, just like knots in pine trees are infections (lines 7-10). After that, Agamemnon anthropomorphizes a state of being, and gives it powerful attributes of Nature (lines 28-32). Nestor replies in the affirmative, comparing events first to a smooth sea, and then when the going gets difficult, events to waves the size of mountains (lines 36-42). Nestor continues using Nature as a metaphor, talking about "storms of fortune" (line 49).
Next, Ulysses has a speech, given to Nestor, in which he uses the idea of a natural hierarchy (lines 86-107). He points out that Sol (here, the Earth) is a king with duty to keep order, but that when the planets (which in the heliocentric model, circle the Earth), "wander" natural disasters result. Aneas agrees, and compares respect due ones' elders with the modesty of morning when beheld by a star (lines 233-335). Using the idea of Nature as virtuous, Agamemnon says to "Speak frankly as the wind" (line 259). This continues the theme of Nature as powerful, though not reliable, since it is the king's job to be reliable.
Ulysses changes the tenor of the conversation when he says that pride is a seed that has grown up in Achilles' dirtiness and must be weeded, or the seeds of the next generation will overthrow all of the Greeks (line 322-327). Then he goes to point out that Achilles is taking all the glory for himself, and it would be better to die a horrible death ("we were better parch in Afric sun") than die under his bitter gaze (lines 375-380). This is the first use of Nature as a negative metaphor by the leaders of the Greeks.
The only mention of Nature in Act II, Scene I, is as a pejorative. Ajax calls someone a toadstool, which presumably slimy and short (line 20). In Act II, Scene II, Troilus again uses the metaphor of wind, this time as an ocean breeze standing in for "consent." In the famous line, he compares Helen to a "pearl, Whose price hath launch'd above a thousand ships" (lines 85-86). Again, a pearl is a valuable natural object, which implies that Helen's worth is intrinsic.
In Act II, Scene III, Agamemnon anthropomorphizes "evasion, wing'd thus swift with scorn" (line 61), and "apprehensions," which presumably can fly as well (line 62). Next, Agamemnon compares Achilles' virtues to fruit that will rot in "in an unwholesome dish" (line 67). Apparently, Achilles is the nasty container. Achilles later is later compared to the moon (traditionally feminine), with whining, moodiness, sulking, and self-centeredness (lines 77-79). Later, Ulysses uses a nature metaphor as sarcasm "The raven chides blackness" when the raven is meant to be Ajax (line 151). Next, Ulysses compared Nestor's wisdom to a shoreline outlining Nestor's experience, and Ajax as "green," meaning immature (lines 184-192). Achilles he compares to a timid deer hiding in the brush, while Ajax is seen as a youthful "flower" (lines 196-202). Generally, the leaders of the Greeks continue their negative figures of speech about human character using Nature, with the exception of praise for each other.
In Act III, Scene I, Pandarus sings a parable about lovers as "buck and doe" shot by "love's bow," though not a fatal blow (line 72). Helen agrees. Paris speaks disparagingly of love as devouring peace, leading to fiery tempers, thoughtlessness, and angry actions (line 76). Pandarus seems to be slightly shocked, and teases Paris by comparing lovers to vipers, a deadly snake (line 76). Interestingly, Pandarus and Helen's views of human nature seem to be very similar to those of the leaders of the Greeks.
In Act III, Scene II, Troilus rejects the idea of lovers as monsters (line 48). Cressida asks if lovers' actions cannot be monstrous, and he reassures her that the only thing monstrous about love is the impossible acts of Nature that lovers swear to each other (line 48). Cressida is no fool, and retorts that those who do not follow through on their actions are monsters, though she phrases it as a question (line 48). Later on in the conversation, Troilus takes Cressida's warning to heart when he swears off boasting about the depth of his love, saying that Nature's truths offer better comparison (lines 118-130). Cressida responds using Troilus's notions about Nature's truths to swear her loyalty to Troilus, saying that her name would be a byword to the end of time if she were false to him (lines130-144). So, they both use Nature as a symbol for their character, but end up switching positions.
In Scene III of Act III, Achilles compares once loyal friends to short-lived butterflies with mealy wings (lines 79-84). Later in the scene, Ulysses calls Ajax a horse, and he be making a dirty joke that Ajax is hung like a horse, and doesn't know what to do with it (lines 135-136), since "nature" is also genitalia (Rubinstein, 1995). "Most abject in regard" could mean that his penis looked small, and "dear in use" could mean that it was used rarely. This sort of dirty joke using a nature idiom was entirely typical of Shakespeare.
Act IV, Scene II, has more use of Nature metaphors. Troilus is again a romantic, talking about being woken up by larks (which were thought to have a pleasant sound), though he had to listen to "ribald crows," presumably his fellow soldiers (lines 12-13). Next, anthropomorphizing a facet of Nature, he says the "dreaming" night will not hide their love any longer and that he won't leave Cressida (lines 14-15). He's continuing to use Nature in a positive way to show his love for her. Later, Pandarus wishes the Earth to hide him (line 79), telling Cressida that she has to go to Antenor (line 81). She calls upon the metaphor of the Earth, saying that the strength of her love is as deep as the center of the earth (lines 93-94). Act IV, Scene III has no Nature metaphors. Act IV, Scene IV has a few; Troilus wishes Cressida "as many farewells as be stars in heaven" (line 41). He also speaks of a starving kiss, tainted by salty, hidden tears (lines 44-45). Pandarus uses a Nature metaphor, saying that his emotions are so tumultuous that he needs to cry, or his heart will break (line 50). So, Troilus and Cressida are both using Nature as a way to first describe good things about themselves, and later the depth of their sorrow.
Act IV, Scene V has its first Nature metaphor when Achilles says to Cressida that he will "take that winter from your lips" (line 30), probably meaning that her demeanor is cold to him. Later in Scene V, Hector refuses to fight Ajax, saying that they're related, and using lots of Nature metaphors to do so: "seed," "hand," "sinew," "blood," "cheek," and so on (lines 141-148). Achilles uses Nature to describe something unpleasant, whereas Hector uses it to describe relationships. They both use it to describe character.
Act V, Scene I has Achilles using nature as a derogatory comment, calling…