python print matrix in spiral using boolean values

Question

I'm looking to print a matrix in spiral way but I'm having some issues understanding when/how exactly to change the boolean values to make it work. This is what I have till now:

A 4x5 matrix

matrix = [[1,2,3,4],[5,6,7,8],[9,10,11,12],[13,14,15,16],[17,18,19,20]]

and the function that should print it

def print_spiral(matrix):
    left = False
    right = True
    down = False
    up = False
    min_x = 0
    max_x = len(matrix) -1 
    min_y = 0
    max_y = len (matrix[0]) - 1 
    x,y = 0, 0
    while True:
        print matrix[x][y]
        if y < max_y and x == min_x:
            y=y+1
        elif y == max_y and x < max_x:
            x=x+1
        elif x == max_x and y > min_y:
            right = False
            y=y-1
        elif y == min_y and x > min_x:
            x = x-1

As it is now, is not printing the matrix in a spiral way but is going in a loop printing the outside rows and columns of the matrix. I'm trying to solve this problem by making use of the boolean left, right, up , down variables but I'm stuck with the logic at this point. Any advices please?!