private String makeColorString() {
        StringBuilder sb = new StringBuilder();
        int square = rubikSize * rubikSize;
        for (int i = 0; i < square; i++) {
            sb.append(buttons[i].getText());
        }
        for (int i = square * 2; i < square * 5; i++) {
            sb.append(buttons[i].getText());
        }
        for (int i = square; i < square * 2; i++) {
            sb.append(buttons[i].getText());
        }
        for (int i = square * 5; i < square * 6; i++) {
            sb.append(buttons[i].getText());
        }
        logger.info("colorString:" + sb.toString());
        return sb.toString();
    }