/* -*- coding: utf-8 -*-
 *
 * 2432.cc:  No.2432 Flip and Move - yukicoder
 */

#include<cstdio>
#include<algorithm>
 
using namespace std;

/* constant */

const int MAX_N = 1000000;
const int INF = 1 << 30;

/* typedef */

typedef long long ll;

/* global variables */

int fs[MAX_N];

/* subroutines */

int calc(int h, int w, int limit = INF) {
  int y = 0, x = 0, dy = 1, dx = 1, l = 0;
  while (l < limit) {
    l++;
    fs[y * w + x] ^= 1;
    y += dy;
    if (y < 0 || y >= h) y -= dy, dy = -dy;
    x += dx;
    if (x < 0 || x >= w) x -= dx, dx = -dx;
    if (y == 0 && x == 0 && dy > 0 && dx > 0) break;
  }
  return l;
}

/* main */

int main() {
  int h, w;
  ll k;
  scanf("%d%d%lld", &h, &w, &k);
  int n = h * w;

  int l = calc(h, w);
  //printf("l=%d\n", l);

  ll q = k / l;
  int r = k % l;
  if (! (q & 1)) fill(fs, fs + n, 0);

  calc(h, w, r);

  for (int i = 0; i < n; i++) {
    putchar(fs[i] ? '#' : '.');
    if ((i + 1 ) % w == 0) putchar('\n');
  }
  return 0;
}