In Part 2, Chapter 5, Carl watches as Emil and Marie hunt ducks. The narrator uses imagery to foreshadow Marie and Emil's violent, disappointing end:
When [Emil] came back, dangling the ducks by their feet, Marie held her apron and he dropped them into it. As she stood looking down at them, her face changed. She took up one of the birds, a rumpled ball of feathers with the blood dripping slowly from its mouth, and looked at the live color that still burned on its plumage.
Emil and Marie "laughed delightedly" when Emil first shot the ducks, but Marie is horrified when Emil brings her the dead birds. Her sudden change in attitude seems to be the result of realizing the full, bloody impact of the sport she was enjoying with Emil. The two of them have been skirting the line of propriety given the fact that Marie is married to someone else. Although they could reasonably pass off the duck hunting as a friendly game, it also seems like a game of courtship. Especially the way Emil places the duck meat in Marie's apron suggests that they are playing house: Emil retrieves meat to feed the family, and he gives it to his "wife" to cook.
Once Emil crosses this line, making their "friendly" game more difficult to distinguish from courtship, Marie takes in the up-close gruesomeness of what they have just done. The bird she picks up still has signs of recent life, but the bullet has turned it into a bloody "ball of feathers." Marie and Emil got caught up in their game and, consequently, they harmed other beings beyond repair. This moment foreshadows the couple's tragic end in two ways. First, the upsetting image of a bird suddenly killed by a thoughtless bullet foreshadows Emil and Marie's own murders. Although Frank shoots them out of rage, his temper is no less thoughtless than the delight that leads Emil and Marie to kill the ducks.
The moment also foreshadows the harm Emil and Marie inflict on others because, once again, they allow themselves to get caught up in the game of their courtship. They may end up dead, but the novel dedicates the last part to Alexandra and Frank's suffering. Frank would never have become a murderer if Emil and Marie had stopped to think about the impact of their infidelity (or so the novel suggests). Meanwhile, Alexandra would not have lost her beloved brother if he had been more cautious.
In Part 4, Chapter 5, Marie learns about Amédée's illness and suddenly feels alone: she knows Emil could just as easily have gotten sick, but she can't take comfort at his side because her love for him is a secret. Marie wanders outside to get away from her house, and the narrator uses imagery to construct a metaphor describing her state of mind:
Marie stole slowly, flutteringly, along the path [...]. The years seemed to stretch before her like the land; spring, summer, autumn, winter, spring; always the same patient fields, the patient little trees, the patient lives; always the same yearning, the same pulling at the chain—until the instinct to live had torn itself and bled and weakened for the last time, until the chain secured a dead woman, who might cautiously be released. Marie walked on, her face lifted toward the remote, inaccessible evening star.
There is no actual chain securing Marie anywhere, but she feels as though there is a metaphorical chain keeping her in place. Marie wants her life to be going somewhere. But as she moves through the years, she keeps cycling back to the same events, the same seasons, and the same landmarks. Everything about her life is as familiar to her as the "patient fields, the patient little trees, the patient lives" she has been impatiently waiting next to forever.
The narrator builds out the metaphor of the chain keeping her in place through vivid imagery. Marie's "instinct to live" is what has been "tearing itself, bleeding, and weakening" against the chain's pull. This instinct is what has been leading her to flirt with Emil and take joy in small delights, even when Frank tries to control her. Now that her instinct to live has stopped trying to resist (i.e. Marie has decided that she will never escape her marriage or get together with Emil), all that is left in the chain is a "dead woman, who might cautiously be released." Marie doesn't believe there is any danger left that she will cheat on Frank or escape her life because her hope has died. The image of the "remote, inaccessible evening star" is a melancholy emblem of her learned helplessness. Try as she might to direct herself toward happiness, she knows she will never get there.
In Part 4, Chapter 7, Frank finds Emil and Marie sleeping together where their families' properties meet. The narrator uses an imagery-packed simile to describe Frank's slow realization that his wife is cheating on him:
In the warm, breathless night air he heard a murmuring sound, perfectly inarticulate, as low as the sound of water coming from a spring, where there is no fall, and where there are no stones to fret it.
Frank is suspiciously investigating his property after coming home to find Emil's horse in his stable. Despite his suspicion, he does not immediately realize what he is hearing when he arrives at the secluded spot where Emil and Marie are having sex. Instead, he notices a "murmuring sound" that is practically unrecognizable. The narrator compares this sound to "the sound of water coming from a spring" when there is nothing to disturb its flow. Whereas water rushing down a waterfall has a distinct sound that can be recognized from far away, as does water burbling over stones, the sound Frank hears is similar to that of a nearly-silent spring. Both the sound Frank hears and the sound of such a spring are so "perfectly inarticulate" that it is hard for a listener to pick out where such a sound is coming from or what it signals until they are upon it.
The imagery embedded in this simile builds suspense as the reader waits for Frank's reaction when he finally feels the sting of betrayal. At the same time, the imagery emphasizes Emil and Marie's naïveté. As far as they know, they are sharing a carefree moment. They do not realize that Frank is there and that their lives are about to end: if they are the spring in the narrator's simile, they are about to crash over the rocks of Frank's temper. If the idea of a "perfectly inarticulate" spring that does not give itself away is difficult to conceptualize, that is because it is practically nonexistent. Even a quiet spring eventually gives itself away to anyone who gets close enough. Emil and Marie have been operating for much of their lives under the fantasy that they can forever conceal their love for each other from the rest of the world. By sleeping together, they have finally pushed this fantasy to its limits.