def box_of(row, col, width=3, height=3, include=True):
    """Return all coordinates in the region of (col, row) as a list.

    Args:
        row (int): The row of the field.
        col (int): The column of the field.
        width (int): The width of the sudoku.
        height (int): The height of the sudoku.
        include (bool): Whether or not to include (row, col).

    Returns:
        list of (int, int): list of pairs (row, column) of all fields in
                            the same box (region).
    """
    grid_x = col - (col % width)
    grid_y = row - (row % height)

    coords = [(grid_y + i, grid_x + j)
              for i in range(height) for j in range(width)]
    if not include:
        coords.remove((row, col))
    return coords