Data and images from   [u]http://en.wikipedia.org/wiki/Double_pendulum[/u]
[img]http://www.phy.ntnu.edu.tw/ntnujava/index.php?action=dlattach;topic=1674.0;attach=2601[/img]

[img]http://www.phy.ntnu.edu.tw/ntnujava/index.php?action=dlattach;topic=1674.0;attach=3503[/img]