The librarian reshelved the damaged collection one row at a time, starting at the bottom where the strongest shelving held the heaviest volumes. Each week she filled another row upward. By the fifth week the stacks were full again — the whole grid packed spine to spine. Then the roof leaked. The water came straight down through the ceiling tiles and hit the topmost row first — the lightest books, the most recently shelved, the ones she'd placed just days before. The lower rows, shielded by the shelves above them, stayed dry. She moved what she could save and started over.