There are two pictures taped to the bedside of Lao Chen's work shed. One is a crayon drawing by his daughter of "Daddy is building a building", and the other is a wrinkled (Interstellar) poster. At 4:40 in the morning, he got up in the dark and tightened the steel bars at an uncapped height of thirty floors. The cold wind blew across his cracked fingers. Just last night, there was still a headlight on here - he was hunched over and wrote formulas on the back of the waste building materials that the workers could not understand: about the evaporation of black holes, about the gravitational constant of eleven-dimensional space.
