This is combination of my old examples. But here we can easily see how to delete, insert items from window at runtime.
I have integrated 6 of the physics motion in one tree. Actually it makes things little complex, say we have colliding balls on one button and when I go somewhere and come back to colliding balls, it should colliding from begin. So, for some motion we need to restore initial position again.
Run the JNLP here :
Jar file is little big, so it will take time.