// #pragma GCC target("avx")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")

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

#define rep(i,n) for(int i = 0; i < (int)n; i++)
#define FOR(n) for(int i = 0; i < (int)n; i++)
#define repi(i,a,b) for(int i = (int)a; i < (int)b; i++)
#define all(x) x.begin(),x.end()
//#define mp make_pair
#define vi vector<int>
#define vvi vector<vi>
#define vvvi vector<vvi>
#define vvvvi vector<vvvi>
#define pii pair<int,int>
#define vpii vector<pair<int,int>>

template<typename T>
void chmax(T &a, const T &b) {a = (a > b? a : b);}
template<typename T>
void chmin(T &a, const T &b) {a = (a < b? a : b);}

using ll = long long;
using ld = long double;
using ull = unsigned long long;

const ll INF = numeric_limits<long long>::max() / 2;
const ld pi = 3.1415926535897932384626433832795028;
const ll mod = 998244353;
int dx[] = {-1, -1, 1, 1};
int dy[] = {-1, 1, -1, 1};

#define int long long

void solve() {
    map<pii, int> inv;
    rep(d, 4) inv[make_pair(dx[d], dy[d])] = d;

    int h, w, k;
    cin >> h >> w >> k;

    vector<string> cycle(h, string(w, '.'));
    int cnt = 0;
    {
        vector<vector<vector<bool>>> done(h, vector<vector<bool>>(w, vector<bool>(4, false)));
        array<int, 3> cur = {0, 0, 3};
        while(!done[cur[0]][cur[1]][cur[2]]) {
            cycle[cur[0]][cur[1]] = (char)('.' + '#' - cycle[cur[0]][cur[1]]);
            done[cur[0]][cur[1]][cur[2]] = true;
            ++cnt;
            int ddx = dx[cur[2]], ddy = dy[cur[2]];
            int nx = cur[0] + ddx;
            int ny = cur[1] + ddy;

            if(nx < 0 || nx >= h) {
                nx = cur[0];
                ddx *= -1;
            }
            if(ny < 0 || ny >= w) {
                ny = cur[1];
                ddy *= -1;
            }

            cur = {nx, ny, inv[make_pair(ddx, ddy)]};
        }
    }

    vector<string> ans(h, string(w, '.'));
    int how_many = k/cnt;
    if(how_many%2 ==1) ans = cycle;
    k %= cnt;

    array<int, 3> cur = {0, 0, 3};
    rep(times, k) {
        ans[cur[0]][cur[1]] = (char)('.' + '#' - ans[cur[0]][cur[1]]);
        int ddx = dx[cur[2]], ddy = dy[cur[2]];
        int nx = cur[0] + ddx;
        int ny = cur[1] + ddy;

        if(nx < 0 || nx >= h) {
            nx = cur[0];
            ddx *= -1;
        }
        if(ny < 0 || ny >= w) {
            ny = cur[1];
            ddy *= -1;
        }

        cur = {nx, ny, inv[make_pair(ddx, ddy)]};
    }

    for(auto e : ans) cout << e << "\n";
}

signed main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    solve();
    return 0;
}