anchor.diff:    }
   
     void _startAnimationLoop() {
  -    _animationStartTime = new Date.now().millisecondsSinceEpoch;
  +    _animationStartTime = new DateTime.now().millisecondsSinceEpoch;
       window.requestAnimationFrame(_animationLoop);
     }
   
  
positive.code:     _droid.src = "/static/images/droid-jetpack-on-front.png";
      _droid.style.left = "${x}px";
      _droid.style.top = "${y}px";
      window.setTimeout(() {
        if (callback != null) {
          callback();
        } else {
          _droid.src = "/static/images/droid-waiting-front.png";
        }
      }, REPOSITION_DURATION);
    }
  
    void _idle() {
  
negative.code:   void _water(String zoneId) {
      window.console.log("Watering zone: ${zoneId}");
      AreaElement zone = document.query("#${zoneId}");
      int x = int.parse(zone.dataset["center-x"]);
      int y = int.parse(zone.dataset["center-y"]);
      int zoneNum = int.parse(zoneId.split("-")[1]);
      _repositionDroid(x, y, () {
        _droid.src = "/static/images/droid-watering-1.png";
  