A primer on Bézier curves

That's pretty comprehensive, but this is the best introduction to Bezier curves I've ever seen: <a href="http://en.wikipedia.org/wiki/File:Bezier_2_big.gif" rel="nofollow">http://en.wikipedia.org/wiki/File:Bezier_2_big.gif</a>

The article has very good illustrations, I am wondering what was the software used.