Digital Huarong Road, there is one of the most stupid methods, anti-clockwise method. When you get to the penultimate line, it's simple, right? Everyone knows that 9X9 is the same. Then you just need to remember that the last number is 12, and the counterclockwise direction is 15 14 13. You can start from 9 and adjust 15 to 654. Then return to the position clockwise, the stupidest way, 100X 100 can do this.