public static void main(String[] args)
  {
    Draw.window(601,600);
    Draw.setTitle("Bouncing Ball");
    Draw.setFill(true);
    int x = 0;
    int y = 0;
    int xDirection = 1;
    int yDirection = 1;
    while(true)
    {
      Draw.setColor(0,0,0);
      Draw.oval(x,y,50,50);
      Util.pause(.005);
      Draw.setColor(255,255,255);
      Draw.oval(x,y,50,50);

      x = x + xDirection;
      if (x>550)
      {
        xDirection = Util.random(2,5);
        xDirection = xDirection*-1;
      }
      if (x<0)
         xDirection = Util.random(2,5);


      y = y + yDirection;
      if (y>550)
      {
        yDirection = Util.random(2,5);
        yDirection = yDirection*-1;
      }
      if (y<0)
        yDirection = Util.random(2,5);

    }

  }