Symbolism, Imagery, Allegory
This symbol appears early in the story in the memories of the first character we encounter. The unnamed married man recalls the square silver shoe buckle of his former sweetheart, Lily. It might not be the sort of thing a man normally remembers about a girl, but there is a reasonable explanation for this after all: while he was begging her to marry him that afternoon fifteen years ago, he kept seeing her shoe. He reflects:
The whole of her seemed to be in her shoe. (3)
From her shoe, he also intuits her response to his proposal even before she actually turns him down: "when it [the shoe] moved impatiently I knew without looking up what she was going to say" (3). Now as he remembers this event, the image of her square silver shoe buckle comes back to him. The particularity of this object (a shoe buckle, of all things!) suggests the vividness of his memory. And of course, because "the whole of her seemed to be in her shoe" (3), the buckle also represents the girl herself, "the woman I might have married" (5), the way things could have gone for him.