from typing import Tuple


def square_box(box_size: float, image_size: Tuple[float, float]) -> Tuple[float, float]:
    """Calculate normalized square box shape.

    :param box_size: initial size
    :param image_size: image shape tuple
    :return: normalized square box shape
    """
    return box_size / image_size[1], box_size / image_size[0]