Dangling, swinging icons.

[Crypty]

Once upon a time I was at my dad's office where he works. It's an advertising agency. I was using one of his co-workers computers(I think the blue G3) and he had this cool thing going on with his desktop icons. When you clicked and held one, it would dangle by the cursor. When you moved it around, it would swing aroud in a realistic manner.

Anyway I just thought it was really cool and i'd like to know if anybody knows how to do this(if it's in the OS) or the name of the program/plug-in that does this.

Thanks.