1, the card material is thick, and the size can be unified into a certain format or depending on the size of the puzzle. 2. Divide riddles into different categories, such as Chinese, mathematics, etc. . . Or animals or plants. . . Wait a minute. 3. Each category is coded according to the serial number of natural numbers. 4. You can write a format vertically (the riddle is at the top left, the answer is at the bottom right, and you can indicate the answer on a page). If you write horizontally, the riddle is above and the purpose is below. 5. Punch a hole in the middle of the upper part of the card and put it in a small wooden box of corresponding size for easy use, search and storage.