About this 3D model

This is a pair of mirror-image rattleback models derived from jasay's original thing. When the "cw" model is spun clockwise it will reverse direction to spin counterclockwise. When the "ccw" model is spun counterclockwise it will reverse direction to spin clockwise. Demo video at http://mysd300.blogspot.com/2010/12/rattleback-twins.html