anchor.diff:    }
   
     void initMarquee() {
  -    canvas = new CanvasElement(width, height);
  +    canvas = new CanvasElement(width: width, height: height);
       canvas.style.cssText = 'display: block;';
       context = canvas.getContext('2d');
       context.font = '66px serif';
  
positive.code:     }
      context.fillRect(0, 0, canvas.width, canvas.height);
      context.strokeStyle = "#ee1";
      context.strokeRect(0, 0, canvas.width, canvas.height, 5);
    }
  
    void showMistake() {
  
negative.code: /*
   * Copyright 2015 Alexander Orlov <alexander.orlov@loxal.net>. All rights reserved.
   * Use of this source code is governed by a BSD-style
   * license that can be found in the LICENSE file.
   */
  
  import 'dart:html';
  import '../core/core.dart';
  /*
   * Copyright 2012 Alexander Orlov <alexander.orlov@loxal.net>. All rights reserved.
   * Use of this source code is governed by a BSD-style
  