#include<bits/stdc++.h>
using namespace std;
using ll = long long;

int main(){
    ll h, w, k; cin >> h >> w >> k;
    k %= 8*h*w;
    vector<vector<int>> a(h,vector<int>(w,0));
    for (ll i = 0; i < k; i++){
        ll ix = i % (2*h);
        ll iy = i % (2*w);
        ll x = (ix < h ? ix : 2*h-1-ix);
        ll y = (iy < w ? iy : 2*w-1-iy);
        a[x][y] ^= 1;
    }
    for (ll i = 0; i < h; i++){
        string ans = "";
        for (ll j = 0; j < w; j++){
            ans += (a[i][j] == 0 ? '.' : '#');
        }
        cout << ans << '\n';
    }
}