anchor.diff:    }
   }
   
  -CanvasMenuState menu_state =
  -  new CanvasMenuState(canvas,
  -    [ new MenuOption("Start", () { gameLoop.state = initial_state; }),
  -      new MenuOption("Quit", () { gameLoop.state = quit_state; } )]);
  +CanvasMenuState menu_state = new CanvasMenuState(canvas, [new MenuOption(
  +    "Start", () {
  +    gameLoop.state = initial_state;
  +  }), new MenuOption("Quit", () {
  +    gameLoop.state = quit_state;
  +  })]);
   
   class QuitState extends SimpleHtmlState {
     void onRender(GameLoopHtml gameLoop) {
  
positive.code: 
    CanvasRenderingContext2D canvas;
  
    CanvasMenuState(this.canvas, options, [selected = 0]) : super(options, selected);
  
    void onRender(GameLoop gameLoop) {
      print("Rendering Menu");
  
negative.code:     coords.add(newHead);
  
      assert(coords.length >= oldLength);
    }
  
    void render(canvas) {
  