def dead_chips(self):
        """Generate the coordinates of all dead chips.

        Yields
        ------
        (x, y)
            The coordinate of a dead chip.
        """
        for x in range(self.width):
            for y in range(self.height):
                if (x, y) not in self:
                    yield (x, y)
Generate the coordinates of all dead chips.

        Yields
        ------
        (x, y)
            The coordinate of a dead chip.