private void searchNewQueens() {
        int y = 0;
        for (int x = 0; x < CELL_SIDE_NUM; x += 2) {
            Cell cell = contents[x][y];
            if (cell.hasCheckerOf(Player.OPPONENT) && cell.hasSimpleChecker()) {
                cell.getChecker().makeQueen();
            }

        }
        y = 7;
        for (int x = 1; x < CELL_SIDE_NUM; x += 2) {
            Cell cell = contents[x][y];
            if (cell.hasCheckerOf(Player.USER) && cell.hasSimpleChecker()) {
                cell.getChecker().makeQueen();
            }
        }
    }