anchor.diff:  
   const int WIDTH = 640;
   const int HEIGHT = 480;
  +
   drawText(CanvasRenderingContext2D canvas, String text, String color) {
     canvas.clearRect(0, 0, WIDTH, HEIGHT);
     canvas.fillStyle = color;
  
positive.code:   }
  
    onRender(GameLoopHtml gameLoop) {
      snake.render(canvas);
    }
  
  
negative.code: 
    SnakeState(String n) {
      this.name = n;
      // XXX Should not be necessary (and is a bogus coupling in any case)
      this.snake = new Snake(canvas);
    }
  
    onKeyDown(KeyboardEvent event) {
  