"""

やるだけ

"""

import sys
from sys import stdin

H,W = map(int,stdin.readline().split())
K = int(stdin.readline())

ans = [0] * (H*W)

state = [-1 for i in range(4*H*W)]

x,y = 0,0
UD = 1
LR = 1

step = 0
while True:

    step += 1
    K -= 1
    ans[x*W+y] ^= 1

    if UD == 0 and x == 0:
        UD = 1
    elif UD == 1 and x == H-1:
        UD = 0
    elif UD == 0:
        x -= 1
    else:
        x += 1

    if LR == 0 and y == 0:
        LR = 1
    elif LR == 1 and y == W-1:
        LR = 0
    elif LR == 0:
        y -= 1
    else:
        y += 1

    UDLR = 2*UD+LR

    idx = UDLR*H*W + x*W + y

    if state[idx] == -1:
        state[idx] = step
    else:
        diff = step - state[idx]
        K %= 2*diff
        state[idx] = step
    
    if K == 0:
        break

ANS = [ "".join(["#" if ans[i*W+j]==1 else "." for j in range(W)]) for i in range(H)]

print (*ANS,sep="\n")