anchor.diff:    Anchor _anchor = new Anchor();
   
     init() {
  -    element.onClick.matches('.MoveButton').listen((e) {
  -      e.preventDefault();
  +    new Timer.periodic(new Duration(seconds: 1), (t) {
         position = (position + 1) % 3;
         invalidate();
       });
  
positive.code: 
    updateView() {
      updateRoot(vRoot()([
        vElement('button', type: 'MoveButton')('Move'),
        vComponent($Box, data: new BoxData(_anchor, position == 0)),
        vComponent($Box, data: new BoxData(_anchor, position == 1)),
        vComponent($Box, data: new BoxData(_anchor, position == 2))
  
negative.code:   }
  
    updateView() {
      updateRoot(vRoot(type: 'Counter')([
        vElement('div')(elapsedSeconds),
        vElement('input', attrs: const {Attr.type: 'text'})
      ]));
    }
  }
  
  