[SWF(backgroundColor=0x000000)]
   public class @ax-animation-ch15-Fireworks extends Sprite
   {
    private var balls:Array;
    private var numBalls:uint = 100;
    private var fl:Number = 250;
    private var vpX:Number = stage.stageWidth / 2;
    private var vpY:Number = stage.stageHeight / 2;
    private var gravity:Number = 0.2;
    private var floor:Number = 200;
    private var bounce:Number = -0.6;