View full lesson: http://ed.ted.com/lessons/the-science-of-symmetry-colm-kelleher When you hear the word symmetry, you might think generally of triangles, butterflies, or even ballerinas. But defined scientifically, symmetry is "a transformation that leaves an object unchanged." Huh? Colm Kelleher unpacks this abstract term and explains how animal's distinct symmetries can tell us more about them -- and ourselves. Lesson by Colm Kelleher, animation by Andrew Foerster.