/// <summary>
        /// Timer event action
        /// </summary>
        /// <param name="source"></param>
        /// <param name="e"></param>
        private void Move(object source, ElapsedEventArgs e)
        {
            gameController.MoveSnake(); //move the snake
            switch (gameController.CheckCollisions())
            {
            case 0:     //dead
                timer.Stop();
                callback.UpdateSnake(null);
                break;

            case 2:     //grow
                callback.UpdateSnake(gameController.GetSnake());
                callback.UpdateBoard(gameController.GetBoard());
                break;

            default:     //go on
                callback.UpdateSnake(gameController.GetSnake());
                break;
            }
        }