code: def view(grid):
      "Show a grid human-readably."
      p_mark, q_mark = player_marks(grid)
      return grid_format % tuple(p_mark if by_p else q_mark if by_q else '.'
                                 for by_p, by_q in zip(*map(player_bits, grid))f view(grid):
      "Show a grid human-readably."
      p_mark, q_mark = player_marks(grid)
      return grid_format % tuple(p_mark if by_p else q_mark if by_q else '.'
                                 for by_p, by_q in zip(*map(player_bits, grid)))
docs: Show a grid human-readably.