#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 998244353;
// constexpr int MOD = 1000000007;
constexpr int DY4[]{1, 0, -1, 0}, DX4[]{0, -1, 0, 1};
constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1};
constexpr int DX8[]{0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U>
inline bool chmax(T& a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U>
inline bool chmin(T& a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

int main() {
  int h, w; ll k; cin >> h >> w >> k;
  vector s(h, vector(w, 0));
  s[0][0] = 1;
  vector dp(h, vector(w, vector(4, -1)));
  dp[0][0][0] = 0;
  bool init = true;
  int i = 0, j = 0, dir = 0, history = 1;
  while (history < k) {
    if (dir & 1) {  // 上
      if (i == 0) {
        dir ^= 1;
      } else {
        --i;
      }
    } else {  // 下
      if (i + 1 == h) {
        dir ^= 1;
      } else {
        ++i;
      }
    }
    if (dir & 2) {  // 左
      if (j == 0) {
        dir ^= 2;
      } else {
        --j;
      }
    } else {  // 右
      if (j + 1 == w) {
        dir ^= 2;
      } else {
        ++j;
      }
    }
    if (init && dp[i][j][dir] != -1) {
      init = false;
      k = (k - history) % ((history - dp[i][j][dir]) * 2) + history;
    }
    s[i][j] ^= 1;
    dp[i][j][dir] = history++;
  }
  REP(i, h) {
    REP(j, w) cout << (s[i][j] ? '#' : '.');
    cout << '\n';
  }
  return 0;
}