Our reader Garnet sets the stage for this video: "Mathematicians have long declared that geometrical hyperbolic space could not be modeled in the real world. Now it's been done, through crochet! Watch TED video science writer Margaret Wertheim explain how the art of crochet emulates sea slugs creating coral structures in hyperbolic space, using art to bring attention to the disappearance of coral through global warming." You can get more information about this presentation here. And, for more TED Talks, don't forget to check out this handy online spreadsheet.