Generate all valid positions in the square around position.

def __skullbomb_radius(self, position):
        """Generate all valid positions in the square around position."""
        #get the boundaries of the explosion
        sb_row, sb_col = position
        left = max(sb_row - 1, 0)  # standard radius or 0 if out of bounds
        right = min(sb_row + 1, 7)  # standard radius or 7 if out of bounds
        top = max(sb_col - 1, 0)
        bottom = min(sb_col + 1, 7)
        for explosion_row in xrange(left, right + 1):
            for explosion_col in xrange(top, bottom + 1):
                yield (explosion_row, explosion_col)