nape example: conveyor belt

package example
{
    import flash.display.DisplayObjectContainer;
    import nape.phys.Body;

    /**
     * ...
     * @author liu wong
     *
     */

    public class conveyorBelt extends baseExample
    {
        private var counter:int = 0;

        public function conveyorBelt(prnt:DisplayObjectContainer):void
        {
            super(prnt);
        }

        override protected function init():void
        {
            super.init();

            space.gravity.setxy(0, 980);

            addWalls();

            const velocityValue:Number = 100;

            var k:int = 10;
            var i:int;

            for (i = 0; i < k; i++)
            {
                var b:Body = addRectangle(320 + 50 * ( -2 * ((i + 1) % 2) + 1), (480 / (k + 1)) * (i + 1), 590, 10, 0, true);
                b.velocity.setxy(velocityValue * ( -2 * (i % 2) + 1), 0);
            }
        }

        override public function update():void
        {
            super.update();

            counter++;

            if (counter >= 30)
            {
                counter = 0;

                var size:Number = random(5, 15);

                addRectangle(20, 20, size, size, 0, false);
            }
        }
    }

}