Flash moving lines

Hey,
Can anyone tell me how these lines are done:

http://www.kirupa.com/developer/flash5/advroll.asp

Those lines are just tweened.

Just create a new movie clip

draw the line and tween it.

Create a new layer and repeat the line drawing process

Put the movie clip on the main timeline and voila.

I know those lines look actionscripted, but they really aren’t. Kirupa said so himself a while back. And if you stare long enough you will see a pattern.