anchor.diff:    }
   
     onRender(GameLoopHtml gameLoop) {
  -    canvas.clearRect(0, 0, WIDTH, HEIGHT);
  +    canvas.clearRect(0, 0, snakePenSizeInPixels.getX(), snakePenSizeInPixels.getY());
       canvas.fillStyle = "rgb(255,165,0)";
  -    canvas.fillRect(0, 0, WIDTH, HEIGHT);
  +    canvas.fillRect(0, 0, snakePenSizeInPixels.getX(), snakePenSizeInPixels.getY());
       canvas.font = "italic bold 24px sans-serif";
       canvas.strokeText("Inside snake pen", 0, 100);
   
  
positive.code: 
    CanvasRenderingContext2D canvas;
  
    static const int WIDTH = 640;
    static const int HEIGHT = 480;
    static const num width = 10;
    static const num height = 10;
  
  
    num initialPauseInMillis = 400;
    num pauseInMillis;
    num tailIncreaseInterval = 5000;
  
  
    String gold_color = "#FFD700";
    String white_color = "#FFFFFF";
  
    void renderSquare(final Coord c, final String color) {
       canvas.fillStyle = color;
       canvas.fillRect(width * c.getX(), height * c.getY(), width, height);
    }
  
    String name;
  
negative.code:     int cwidth = canvas.canvas.width;
      int cheight = canvas.canvas.height;
  
      int cowidth = (cwidth / gridBlockWidth).round();
      int coheight = (cheight / gridBlockWidth).round();
  
      this.snake = new Snake(cowidth, coheight);
  
  