The Crochet Coral Reef project, by Margaret and Christine Wertheim and the Institute For Figuring, responds to the environmental crisis of global warming and the escalating problem of oceanic plastic trash. Residing at the intersection of mathematics, marine biology, handicraft, and community art practice, the Crochet Coral Reef highlights not only the damage humans do to the earth’s environment, but also our power for positive action. The project constitutes an elegiacally beautiful, artistically complex, and socially powerful way to bring citizens together around a devastating ecological challenge—the survival of the coral reefs and marine ecologies throughout the world.