Untitled

 # down-right sudoku
      
    if (x>8 and y>11):
        
           #joint square
        if (x>11 and x<15 and y<15):
            for i in range(6, 21):
               if Matrix[y][i] == n:
                return False
     
            for i in range(6, 21):
             if Matrix[i][x-3] == n:
                 return False
            
            x0 = (x//3)*3
            y0 = (y//3)*3
            for i in range(0, 3):
             for j in range(0, 3):
              #  print(board[y0+i][x0+j])
                if Matrix[y0+i][x0+j] == n:
                    return False
            return True 
        elif x>=15 and y<15:
            for i in range(12, 21):
               if Matrix[y][i] == n:
                return False 

            for i in range(15, 21):
                if Matrix[i][x-3] == n:
                 return False
           
            x0 = (x//3)*3
            y0 = (y//3)*3
            for i in range(0, 3):
              for j in range(0, 3):
              #  print(board[y0+i][x0+j])
                if Matrix[y0+i][x0+j] == n:
                    return False
            return True
        else:
            for i in range(9, 18):
              print(Matrix[y][i])
              if Matrix[y][i] == n:
                return False

            for i in range(15, 21):
                if Matrix[i][x]   == n:
                   return False
            if Matrix[12][x+3] ==n:
                return False
            elif Matrix[13][x+3] ==n:
                return False
            elif Matrix[14][x+3] ==n:
                return False
            x0 = (x//3)*3
            y0 = (y//3)*3
            for i in range(0, 3):
              for j in range(0, 3):
              #  print(board[y0+i][x0+j])
                if Matrix[y0+i][x0+j] == n:
                   return False
            return True