import sys
from itertools import permutations
from heapq import *

input = lambda :sys.stdin.readline().rstrip()
mi = lambda :map(int,input().split())
li = lambda :list(mi())

class SegmentTree:
    def __init__(self, init_val, segfunc, ide_ele):
        n = len(init_val)
        self.segfunc = segfunc
        self.ide_ele = ide_ele
        self.num = 1 << (n - 1).bit_length()
        self.tree = [ide_ele] * 2 * self.num
        self.size = n
        for i in range(n):
            self.tree[self.num + i] = init_val[i]
        for i in range(self.num - 1, 0, -1):
            self.tree[i] = self.segfunc(self.tree[2 * i], self.tree[2 * i + 1])

    def update(self, k, x):
        k += self.num
        self.tree[k] = self.segfunc(self.tree[k],x)
        while k > 1:
            k >>= 1
            self.tree[k] = self.segfunc(self.tree[2*k], self.tree[2*k+1])

    def query(self, l, r):
        if r==self.size:
            r = self.num

        res = self.ide_ele

        l += self.num
        r += self.num
        right = []
        while l < r:
            if l & 1:
                res = self.segfunc(res, self.tree[l])
                l += 1
            if r & 1:
                right.append(self.tree[r-1])
            l >>= 1
            r >>= 1

        for e in right[::-1]:
            res = self.segfunc(res,e)
        return res

H,W = mi()
K = int(input())

visit = [[[-1]*W for i in range(H)] for d in range(4)]
visit[0][0][0] = 0

trail = [(0,0,0)]
loop_l = -1
while True:
    d,h,w = trail[-1]

    if d & 1 == 0:
        if h+1 < H:
            h += 1
        else:
            d ^= 1
    else:
        if 0 <= h-1:
            h -= 1
        else:
            d ^= 1

    if d & 2 == 0:
        if w+1 < W:
            w += 1
        else:
            d ^= 2
    else:
        if 0 <= w-1:
            w -= 1
        else:
            d ^= 2
    
    if visit[d][h][w] == -1:
        visit[d][h][w] = len(trail)
        trail.append((d,h,w))
    else:
        loop_l = visit[d][h][w]
        break

assert len(trail) <= 4 * H * W

if K <= len(trail):
    res = [[0]*W for i in range(H)]
    for d,h,w in trail[:K]:
        res[h][w] ^= 1

    for i in range(H):
        S = "".join(["." if res[i][j]==0 else "#" for j in range(W)])
        print(S)
    exit()


L = len(trail) - loop_l
loop_cnt = (K-loop_l) // L

for i in range(H):
    for j in range(W):
        visit[0][i][j] = 0
res = visit[0]

for d,h,w in trail[:loop_l]:
    res[h][w] ^= 1
for d,h,w in trail[loop_l:]:
    if L & 1:
        res[h][w] ^= 1
for d,h,w in trail[loop_l:loop_l+((K-loop_l)%L)]:
    res[h][w] ^= 1

for i in range(H):
    S = "".join(["." if res[i][j]==0 else "#" for j in range(W)])
    print(S)