h, w = map(int, input().split())
from math import gcd
l = h * w // gcd(h,w) * 2
k = int(input()) % l

x,y = 0,0
dx,dy = 1,1

s = [["." for j in range(w)] for i in range(h)]

for _ in range(k):
    if s[x][y] == ".":
        s[x][y] = "#"
    else:
        s[x][y] = "."

    if x + dx < 0 or x + dx >= h:
        dx *= -1
    else:
        x += dx
    if y + dy < 0 or y + dy >= w:
        dy *= -1
    else:
        y += dy

for i in s:
    print("".join(i))