Not to be read literally, but as metaphor

I think anyone searching for answers as to "what" or "why" the wall exists is bound to be frustrated by this narrative. The woman spends very little time pondering these reasons, or even thinking about life beyond her boundaries. The Wall is not a science fiction story or a mystery that requires a solution.

I believe it's much more satisfying to see the woman's existence as a microcosm of humanity, and the inability of people to fully articulate their need and desire for meaningful connection; she says this explicitly near the end, as she hunts alone in the snow, remarking that we are an "infinite army of dead" and "if we could recognize, in time, that [love] was our only option."

There is very clear symbolism in the white cat, white crow, and calf; the narrator identifies with and sees herself and, by extension, all humanity in the animals. Like the cat, born pure and destined to be taken away by nature. Or the crow, rejected by her own kind, alone and not knowing why. And the calf, taken from its mother not by force of nature, but by the chaos of man.

The sudden appearance of the man is representative of the unpredictable pains of life, which can take love away from us, throw us into ruin. Similarly, the black cloth hanging in the trees is foreboding; we wonder why such ill omens appear to us, and what fears and anxieties they foretell. It doesn't matter how such things came to be, they simply are, and we must acknowledge them as forces in our lives.

The daily struggles, small victories, incomprehensible tragedies, and the simple pleasures that sometimes escape us -- the bleating of a calf for its mother, the comfort of a cat sharing a bed, warm winds across spring grass, the easy and knowing companionship of a dog, the satisfaction of a day's work, sun on one's face -- all of these things are what this story asks us to consider. At least, that is how it seemed to me, and that is a profound lesson for anyone.