private String createColor() {
        String col = "";
        for (int i = 0; i < 6; i++) {
            int ran = (int) Math.round(Math.random() * ((int) (i / 2) == (i / 2) ? 12 : 15));
            switch (ran) {
                case 10:
                    col += "A";
                    break;
                case 11:
                    col += "B";
                    break;
                case 12:
                    col += "C";
                    break;
                case 13:
                    col += "D";
                    break;
                case 14:
                    col += "E";
                    break;
                case 15:
                    col += "F";
                    break;
                default:
                    col += Integer.toString(ran);
                    break;
            }
        }
        return col;
    }