[x] Blank screen appears 
[x] Movable (left and right arrows) paddle appears [paddle object]
	[x] Don't need to press again to move (use boolean)
[x] Balls appear in a fixed initial location but random velocity. [ball object]
	[x] Bounce off walls (correctly)
	[x] Get constant velocity even if lots of events [timer]
	[x] Bounce off paddle
	[x] Game ends when no more balls on screen
[x] Balls accelerate with gravity [.move method enhancement]
[x] Balls stop when they collide 
[x] Balls obey conservation of momentum [see physics text]
[x] Balls can have different colors
[x] Balls can have different sizes/masses
[x] The score changes: point for bounce is prop to # balls on screen at the time (so reward for keeping lots in air)
[x] Change the speed of the paddle
[x] Make some balls have rings like Saturn
	[ ] Fancy rings that are rotated arcs (using transparent transform)
[x] Rename with planet name, which inherits from Ball. 
	[ ] RingedPlanet inherits from Planet?
[x] Teleport colliding balls apart
[x] Pause button works
[x] Keep paddles from getting stuck on edges (it's that keyups stop it)
[x] Make random stars in the background
[ ] Make the paddle accelerate
[ ] Draw portal, out of which the planets fall
[ ] Screen refresh rate is correct
[ ] Have it use less CPU power (pauses)
[ ] Scoring:
	[ ] Have a target at which point you win
	[ ] Lose points when one gets by, lose more if its faster and there are fewer balls
	[ ] Gain more points for bouncing a fast ball?
	[ ] CONSIDER: Fix so it only counts 1 collision (like teleport colliding ball up further]