This article is a little more involved than the first article and it involves some basic trigonometry. Don't worry, it's not that difficult to follow, even if you can't remember much math from your high school days!
I've assumed that you are using Flash MX or Flash MX 2004 and that know how to add ActionScript to a movie. I've used ActionScript 1.0 for the examples.You can download the source files for the tutorial from the blue Properties box that contains the article PDF. There's a heading titled Code Download and you can click the Details link next to it to get the zip file. The download includes the starter files you'll need as well as the completed files.