anchor.diff:      }
       context.fillRect(0, 0, canvas.width, canvas.height);
       context.strokeStyle = "#ee1";
  -    context.strokeRect(0, 0, canvas.width, canvas.height, 5);
  +    context.strokeRect(0, 0, canvas.width, canvas.height);
     }
   
     void showMistake() {
  
positive.code: 
      attachHandler();
      initMarquee();
      document.body.elements.add(canvas);
      redraw();
  
  // todo make the draw function a typedef
  
negative.code:   }
  
    void initMarquee() {
      canvas = new CanvasElement(width: width, height: height);
      canvas.style.cssText = 'display: block;';
      context = canvas.getContext('2d');
      context.font = '66px serif';
  