Late at night, a kerosene lamp cast flickering light and shadows on the earthen kang bed.
Ji Xiaosong, draped in Xu Weidong's old work jacket, sat before the low kang table, a yellowed copy of *Elementary Algebra* spread open in front of her.
Her fingertips gently traced the edges of the pages, which had become frayed from constant use.
"Xiaosong, your pupils' focal distance has not changed for the past 37 minutes."
Ji Dan's voice came from the shadows. It was adjusting the tightness of Xu Nian'an's swaddling clothes with nanometer-level precision. "Are you deep in thought, or simply spacing out?"
Outside the window, the whistle of the steel mill could be faintly heard.
Ji Xiaosong came back to her senses and looked at her three sleeping children. Zhigang's little fists were clenched tight, Zhitie was sprawled out, and Nian'an was as quiet as a kitten.
"Ji Dan," she began suddenly, her voice very soft, "tell me... how much can we really change?"
