Mimi Koehl tinkers with machines. Some are so tiny they can't be seen by the naked eye, and some disappeared millions of years ago. But Mimi isn't a mechanic. She's a biomechanist. Mimi Koehl uses engineering and physics to study the designs of living things that fly, swim, drift, and crawl. She loves solving riddles about how creatures--from feathered dinosaurs to flying frogs--live and move. Mimi's curiosity has led her into all kinds of natural...