Build an interactive Java graphic!

You can really build whatever you want, but follow these steps:

1. Use the Java Graphics or Graphics2D context
2. Do your drawings on a custom inner class (like canvas)
3. Your drawing should be dynamic in some way.
4. You can use a timer and animation to create an animation
5. You can use user input to get information from the user (a drawing program)
6. It needs to do a little more than just drawing the picture.
7. It shouldn't simply be abstract. It should look like something