This is a good animation of them working (animated GIF): http://www.grc.nasa.gov/WWW/TECB/videos/animation_TDC_01_jeff.gif http://www.grc.nasa.gov/WWW/TECB/vide

This is a good animation of them working (animated GIF): http://www.grc.nasa.gov/WWW/TECB/videos/animation_TDC_01_jeff.gif http://www.grc.nasa.gov/WWW/TECB/videos/animation_TDC_01_jef...