public void actionPerformed(ActionEvent e) {
    Control.incrementValue();// changes from X to O
        if (ok) { //to not override a cell
            switch (Control.getValue() % 2) {
            case 0:
                setIcon(X);
                value=0;
                break;
            case 1:
                setIcon(O);
                value=1;
                break;
            }
            ok = false;
        }
    if(Control.gameOver()){
        Control.endGame();
    }

}