import numpy as np

matrix = np.random.randint(2, size=(10, 10))
print(matrix)
M, N = matrix.shape

walked = []
zonesCount = []


def pathCount(x, y):
    if x < 0 or y < 0 or x >= M or y >= N:
        return 0
    if matrix[x, y] == 1:  # I replaced * by 1 and . by 0 for easier generation
        return 0
    if (x, y) in walked:
        return 0

    walked.append((x, y))

    count = 1

    for i in [x - 1, x, x + 1]:
        for j in [y - 1, y, y + 1]:
            if (i, j) != (x, y):
                count += pathCount(i, j)

    return count

for x in range(M):
    for y in range(N):
        if not (x, y) in walked:
            zonesCount.append(pathCount(x, y))

print('Max zone count :', max(zonesCount))

[[0 0 1 0 0 0 1 0 1 0]
 [1 0 1 0 0 0 1 0 1 1]
 [0 1 0 0 1 0 0 1 1 1]
 [0 0 1 0 0 0 1 1 0 1]
 [1 0 1 1 1 1 0 1 1 0]
 [1 0 1 1 1 1 0 1 1 0]
 [0 0 0 1 1 1 0 0 0 0]
 [1 0 0 1 1 0 0 1 1 0]
 [0 1 0 1 0 0 1 0 1 1]
 [0 1 1 0 0 0 1 0 1 0]]
Max zone count : 50