#int(input())
#map(int, input().split())
#list(map(int, input().split()))

H, W = map(int, input().split())
K = int(input())

from math import gcd
N = 2 * H * W // gcd(H, W)

K %= N

ans = [[0] * W for i in range(H)]
for i in range(K):
    ux, vx = divmod(i, 2*H)
    uy, vy = divmod(i, 2*W)
    # if ux % 2 == 1:
    #     vx = 2*H - vx
    # if uy % 2 == 1:
    #     vy = 2*W - vy
    vx = min(vx, 2*H-vx-1)
    vy = min(vy, 2*W-vy-1)
    # print(H, W, vx, vy)

    ans[vx][vy] += 1

for i in range(H):
    a = ""
    for j in range(W):
        if ans[i][j] % 2 == 0:
            a += "."
        else:
            a += "#"
    print(a)