private function onEnterFrame(event:Event):void
    {
     moveBall();
     var target:Point = reach(segments[0], ball.x, ball.y);
     for(var i:uint = 1; i < numSegments; i++)
     {
      var segment:animation_ch14_Segment = segments[i];
      target = reach(segment, target.x, target.y);
     }
     for(i = numSegments - 1; i > 0; i--)
     {
      var segmentA:animation_ch14_Segment = segments[i];
      var segmentB:animation_ch14_Segment = segments[i - 1];
      position(segmentB, segmentA);
     }
     checkHit();
    }