Python:Gann square of 9

class GannSquare():
    """An container object for Gann Square"""

    def __init__(self, size):

        """ attributes and method of Gann Square
            input parameters: size
            output returned: an object along with its attributes
        """
        self.size = size
        self.even_size = size % 2 == 0
        self.odd_size = size % 2 == 1
        self.num_elements = size ** 2
        
        self.matrix = self.generate()
        
        self.horizontal_axis = self.get_horizontal_axis()
        self.vertical_axis = self.get_vertical_axis()
        self.diagonal_1 = self.get_diagonal_1()
        self.diagonal_2 = self.get_diagonal_2()
        self.diagonal_axis = self.get_diagonal_axis()
        
    def generate(self):
        """
        generate a Gann Square based on the input parameter size
        """
        from numpy import array
        NORTH, SOUTH, EAST, WEST = (0, 1), (0, -1), (1, 0), (-1, 0) # directional vectors
        clockwise = {
            WEST:NORTH,
            NORTH: EAST, 
            EAST: SOUTH, 
            SOUTH: WEST
        } # clockwise transformation
        
        RIGHT, LEFT = 1, -1
        # forward or backward increment

        if self.size < 1:
            raise ValueError
        x, y = self.size // 2, self.size // 2 
        # the middle of the box
        dx, dy =  WEST # initial direction
        inc = LEFT # backward increment

        G = [[None] * self.size for _ in range(self.size)]
        
        count = 0

        while True:
            count += 1
            G[x][y] = count # visit
            # follow predefined direction
            _dx, _dy = clockwise[dx,dy]
            _x, _y = x +inc* _dx, y +inc* _dy

            if (0 <= _x < self.size and 0 <= _y < self.size and
                G[_x][_y] is None): 
                # in the box
                x, y = _x, _y
                dx, dy = _dx, _dy

            else: # fill in the box
                x, y = x +inc* dx, y +inc* dy
                if not (0 <= x < self.size and 0 <= y < self.size):
                    return array(G) # out of the box
    
    def display_matrix(self):
        width = len(str(max(e for row in self.matrix for e in row if e is not None)))
        fmt = "{:0%dd}" % width
        for row in self.matrix:
            print(" ".join("_"*width if e is None else fmt.format(e) for e in row))
            
    def get_horizontal_axis(self):
        return self.matrix[:,self.size//2]
    
    def get_vertical_axis(self):
        return self.matrix[self.size//2, :]
    
    def get_diagonal_1(self):
        diagonal_1 = []
        for i in range(self.size):
            diagonal_1.append(self.matrix[i,self.size-i-1])
        return diagonal_1
    
    def get_diagonal_2(self):
        diagonal_2 = []
        for i in range(self.size):
            diagonal_2.append(self.matrix[i,i])
        return diagonal_2
    
    def get_diagonal_axis(self):
        from numpy import concatenate
        return concatenate((self.diagonal_1, self.diagonal_2))

Here is what the above code is Doing:
1. The __init__ method is called when the object is created.
2. The __init__ method takes the size of the Gann Square as an input parameter.
3. The __init__ method then calls the generate method to generate the Gann Square.
4. The generate method uses the size parameter to generate the Gann Square.
5. The generate method returns the Gann Square as a matrix.
6. The __init__ method then calls the get_horizontal_axis, get_vertical_axis, get_diagonal_1, get_diagonal_2, and get_diagonal_axis methods to generate the horizontal axis, vertical axis, diagonal 1, diagonal 2, and diagonal axis.
7. The get_horizontal_axis, get_vertical_axis, get_diagonal_1, get_diagonal_2, and get_diagonal_axis methods use the matrix to generate the horizontal axis, vertical axis, diagonal 1, diagonal 2, and diagonal axis.
8. The get_horizontal_axis, get_vertical_axis, get_diagonal_1, get_diagonal_2, and get_diagonal_axis methods return the horizontal axis, vertical axis, diagonal 1, diagonal 2, and diagonal axis.
9. The __init__ method then assigns the horizontal axis, vertical axis, diagonal 1, diagonal 2, and diagonal axis to the object.
10. The __init__ method then returns the object along with its attributes.