Near the beginning of the story, the narrator spends time explaining the depth of Mary’s love for her husband Patrick, using a simile in the process:
She loved to luxuriate in the presence of this man, and to feel—almost as a sunbather feels the sun—that warm male glow that came out of him to her when they were alone together.
Here, the narrator describes how Mary “luxuriate[s]” in Patrick’s presence “as a sunbather feels the sun.” This simile establishes that, even after years of marriage, Mary still loves her husband deeply and admires him. At the same time, it also communicates that Mary has internalized patriarchal notions of “the man of the house” being a dominant force to which a woman is supposed to be subservient. Mary notably does not see herself as a sun, but as one who basks in “the warm male glow” of her husband’s sun.
Mary’s way of viewing herself and her husband likely stems from marriage expectations that were popular in the mid-20th century—women were meant to be passive and docile and men were meant to be strong and in charge. Mary ultimately reverses these marriage roles by killing her husband after he threatens to leave her, an extreme way of embracing her power and taking away his.
Near the end of the story, the detectives at the Maloney home discuss what sort of weapon was used to murder Patrick, using a simile in the process:
"That's the hell of a big club the gut must've used to hit poor Patrick," one of them was saying. "The doc says his skull was smashed all to pieces just like from a sledge-hammer."
"That's why it ought to be easy to find."
"Exactly what I say."
The simile that one of the detectives uses here—in which he states that Patrick’s skull “was smashed all to pieces just like from a sledge-hammer”—helps readers to understand just how hard Mary hit her husband with the frozen leg of lamb when she killed him. In addition to a sledgehammer, the detectives also hypothesize that the weapon could have been a large club of some kind.
Readers are aware in this scene that it was a mere leg of lamb—combined with Mary’s wrath—that caused Patrick’s skull to shatter so dramatically, and are therefore aware that the detectives are underestimating Mary, likely because she is a pregnant housewife who they view as not being capable of such a violent (and effective) act.