http://enjoy.phy.ntnu.edu.tw/mod/resource/view.php?id=8505

interesting swf.
[url=http://enjoy.phy.ntnu.edu.tw/mod/resource/view.php?id=8505]http://enjoy.phy.ntnu.edu.tw/mod/resource/view.php?id=8505[/url]
i registered  :D


i will try analytic curve later, looks more easy for circle.

thanks