text: def writeHigh(b, value):
      return (b & 0x0f) | (value << 4)
  
  
  def readHigh(b):
      return (b & 0xf0) >> 4
  
  
  def writeLow(b, value):
      return (value) | (b & 0xf0)
  
  
  def readLow(b):
      return b & 0x0f
  
  
  b = 0x00
  # A的位置1
  b = writeLow(b, 1)
  while readLow(b) <= 9:
  
      b = writeHigh(b, 1)
      while readHigh(b) <= 9:
          if(readHigh(b) % 3 != readLow(b) % 3):
              print([readLow(b), readHigh(b)])
  
          b = writeHigh(b, readHigh(b) + 1)
          # print('highbits', readHigh(b))
  
      b = writeLow(b, readLow(b) + 1)
      # print('lowbits', readLow(b))
  