#include <bits/stdc++.h>

using namespace std;
using ll = long long;

int main(){

    ll H, W, K, x=1, y=1, h=1, w=1;
    cin >> H >> W >> K;
    K %= (H*W*8);
    vector<vector<int>> S(H+1, vector<int>(W+1));

    for (int i=0; i<K; i++){
        S[h][w] ^= 1;
        if (1 <= h+x && h+x <= H) h = h+x;
        else x *= -1;
        if (1 <= w+y && w+y <= W) w = w+y;
        else y *= -1;
    }

    for (int i=1; i<=H; i++){
        for (int j=1; j<=W; j++) cout << (S[i][j] ? '#' : '.');
        cout << endl;
    }

    return 0;
}