private void NewGame()
        {
            gameBoard.Reset();
            playingBoard.Reset();

            CreateAI();

            TextBlockAITime.Text       = "";
            TextBlockAISteps.Text      = "";
            TextBlockAIBestResult.Text = "";
            TextBlockResult.Text       = "";

            if (gameAIX != null)
            {
                playerSign = TicTacToeSign.Sign_O;
                NextMove(gameAIX, TicTacToeSign.Sign_X);
            }
            else
            {
                playerSign = TicTacToeSign.Sign_X;
            }
        }