Area X itself serves as a symbol of the uncontrollable and unknowable. The pristine wilderness is filled with strange fungi, mutated plants, and doppelgangers of DNA that enter it (most notably human clones). Though the whole area is symbolic, the border and the Tower represent specific ideas of separation and transition.

The glistening border marks the boundary between the known and unknown, between reality and the mysterious. When Control visits the border, its eeriness is palpable: “swirled a scintillating, questing white light, a light that fizzed and flickered and seemed always on the point of being snuffed out but never was” (135). From the expedition reports, the border takes three to ten hours to pass through and can feel like going underwater, seeing constellations from far and near, or like a vast, expanding plain, proving the border does not give the same experience to everyone. Like the others, Control is struck by the bizarre border, how it works, and why it offers a door for entrance. Area X seems to welcome people inside, transitioning them from one world to the next, but also separates them from fully understanding it. Because the idea of borders is symbolic of the transition, separation, and the unknowable, the word “border” is repeated 123 times in the novel.