Letter Cube-Puzzle Game

Application description:
This is an application that tests the agility and memory of the eyes, and adjusts the difficulty of the game according to the number of letters.
Features:
1. Set a minimum of 5 digits and a maximum of 26 digits for generating letters;
2. After the generation, begin to memorize the position of the randomly generated letters in the lower letter box, and at the same time start to memorize the time countdown. After the time is over, the 26 letters below are hidden,
The letter blocks below must be turned out in the order of the letters generated above; if you click the wrong one, the challenge fails;
3. The position of the 26 letters below is randomly placed after each regeneration, not fixed.