Ask the hand tour to rotate the wooden ruler to see the letter change.

1. First of all, you can get a random clue from the paper that asked about the task of rotating the wooden ruler in the mobile game, as shown in figure BCXJU. In the rotating wooden ruler, two groups of letters will be given, and the changes of letters need to be checked.

2. Then turn the wooden ruler and see that the letters in the second group are ATULWXKJQBCM. According to the clues of BCXJU, we can find that the corresponding positions of BCXJU letters are the tenth, eleventh, sixth, eighth and third places respectively.

3. Finally, according to the positions 10, 1 1, 6, 8 and 3, find the letters in this position in the first group of wooden rulers. The number 10 is X, the number 1 1 is Y, the number 6 is F, the number 8 is S, and the number 3 is C. The answer to the letter change clue of the rotating wooden ruler in the mobile game is XYFSC.