Sounds cool, but if the balls are never still, and you are using realistic physics, then would they be flying around every where all the time? Also, if all the balls never stop moving, and each ball has a certain amount of energy because of it''s movement, and you keep throwing more balls in, then the total energy of balls on the screen will increase, and this could result in a mess of balls bouncing around the screen in a total unpredictable franatic pattern. One thing about puzzle games is that the player should be able to anticipate what will happen because of his or her actions. So, if you don''t want this to happen, you would have to not use realistic physics. Besides, with a puzzle game you need pieces to line up in a certain way to clear them, and realistic physics are not very conducive to making stuff stay still.

You mentioned something about balls connected by springs. Would the center of the spring be stationary, and then the spring flexes so that the balls move in relation to the center of the spring? Or would the spring just flex and you would try to figure out what that would do?

What if it was like a game of pool and you could move the balls around by throwing more balls in? Then, by making different sized and massed balls you could have a veriance in the effect the balls have on each other. Now, make the friction coefficient significantly large so that the balls don''t go flying in all directions all the time.

I think that''s the key, you will need to incorporate friction. In a puzzle game the pieces need to consolidate for a moment so that they can match up and clear off. Think of the name, PUZZLE game. If you were trying to put together a jigsaw puzzle and all the pieces were constantly moving you would never get it done.

Are you even trying to be intelligent?
'cuz if you are, it ain't workin'