/* #region Head */

// #include <bits/stdc++.h>
#include <algorithm>
#include <array>
#include <bitset>
#include <cassert> // assert.h
#include <cmath>   // math.h
#include <cstring>
#include <ctime>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <memory>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
using namespace std;

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pll = pair<ll, ll>;
template <class T> using vc = vector<T>;
template <class T> using vvc = vc<vc<T>>;
using vll = vc<ll>;
using vvll = vvc<ll>;
using vld = vc<ld>;
using vvld = vvc<ld>;
using vs = vc<string>;
using vvs = vvc<string>;
template <class T, class U> using um = unordered_map<T, U>;
template <class T> using pq = priority_queue<T>;
template <class T> using pqa = priority_queue<T, vc<T>, greater<T>>;
template <class T> using us = unordered_set<T>;

#define REP(i, m, n) for (ll i = (m), i##_len = (ll)(n); i < i##_len; ++(i))
#define REPM(i, m, n) for (ll i = (m), i##_max = (ll)(n); i <= i##_max; ++(i))
#define REPR(i, m, n) for (ll i = (m), i##_min = (ll)(n); i >= i##_min; --(i))
#define REPD(i, m, n, d) for (ll i = (m), i##_len = (ll)(n); i < i##_len; i += (d))
#define REPMD(i, m, n, d) for (ll i = (m), i##_max = (ll)(n); i <= i##_max; i += (d))
#define REPI(itr, ds) for (auto itr = ds.begin(); itr != ds.end(); itr++)
#define REPIR(itr, ds) for (auto itr = ds.rbegin(); itr != ds.rend(); itr++)
#define ALL(x) begin(x), end(x)
#define SIZE(x) ((ll)(x).size())
#define PERM(c)                                                                                                        \
    sort(ALL(c));                                                                                                      \
    for (bool c##p = 1; c##p; c##p = next_permutation(ALL(c)))
#define UNIQ(v) v.erase(unique(ALL(v)), v.end());
#define CEIL(a, b) (((a) + (b)-1) / (b))

#define endl '\n'

constexpr ll INF = 1'010'000'000'000'000'017LL;
constexpr int IINF = 1'000'000'007LL;
constexpr ll MOD = 1'000'000'007LL; // 1e9 + 7
// constexpr ll MOD = 998244353;
constexpr ld EPS = 1e-12;
constexpr ld PI = 3.14159265358979323846;

template <typename T> istream &operator>>(istream &is, vc<T> &vec) { // vector 入力
    for (T &x : vec) is >> x;
    return is;
}
template <typename T> ostream &operator<<(ostream &os, const vc<T> &vec) { // vector 出力 (for dump)
    os << "{";
    REP(i, 0, SIZE(vec)) os << vec[i] << (i == i_len - 1 ? "" : ", ");
    os << "}";
    return os;
}
template <typename T> ostream &operator>>(ostream &os, const vc<T> &vec) { // vector 出力 (inline)
    REP(i, 0, SIZE(vec)) os << vec[i] << (i == i_len - 1 ? "\n" : " ");
    return os;
}

template <typename T, size_t _Nm> istream &operator>>(istream &is, array<T, _Nm> &arr) { // array 入力
    REP(i, 0, SIZE(arr)) is >> arr[i];
    return is;
}
template <typename T, size_t _Nm> ostream &operator<<(ostream &os, const array<T, _Nm> &arr) { // array 出力 (for dump)
    os << "{";
    REP(i, 0, SIZE(arr)) os << arr[i] << (i == i_len - 1 ? "" : ", ");
    os << "}";
    return os;
}

template <typename T, typename U> istream &operator>>(istream &is, pair<T, U> &pair_var) { // pair 入力
    is >> pair_var.first >> pair_var.second;
    return is;
}
template <typename T, typename U> ostream &operator<<(ostream &os, const pair<T, U> &pair_var) { // pair 出力
    os << "(" << pair_var.first << ", " << pair_var.second << ")";
    return os;
}

// map, um, set, us 出力
template <class T> ostream &out_iter(ostream &os, const T &map_var) {
    os << "{";
    REPI(itr, map_var) {
        os << *itr;
        auto itrcp = itr;
        if (++itrcp != map_var.end()) os << ", ";
    }
    return os << "}";
}
template <typename T, typename U> ostream &operator<<(ostream &os, const map<T, U> &map_var) {
    return out_iter(os, map_var);
}
template <typename T, typename U> ostream &operator<<(ostream &os, const um<T, U> &map_var) {
    os << "{";
    REPI(itr, map_var) {
        auto [key, value] = *itr;
        os << "(" << key << ", " << value << ")";
        auto itrcp = itr;
        if (++itrcp != map_var.end()) os << ", ";
    }
    os << "}";
    return os;
}
template <typename T> ostream &operator<<(ostream &os, const set<T> &set_var) { return out_iter(os, set_var); }
template <typename T> ostream &operator<<(ostream &os, const us<T> &set_var) { return out_iter(os, set_var); }
template <typename T> ostream &operator<<(ostream &os, const pq<T> &pq_var) {
    pq<T> pq_cp(pq_var);
    os << "{";
    if (!pq_cp.empty()) {
        os << pq_cp.top(), pq_cp.pop();
        while (!pq_cp.empty()) os << ", " << pq_cp.top(), pq_cp.pop();
    }
    return os << "}";
}

void pprint() { cout << endl; }
template <class Head, class... Tail> void pprint(Head &&head, Tail &&...tail) {
    cout << head;
    if (sizeof...(Tail) > 0) cout << ' ';
    pprint(move(tail)...);
}

// dump
#define DUMPOUT cerr
void dump_func() { DUMPOUT << endl; }
template <class Head, class... Tail> void dump_func(Head &&head, Tail &&...tail) {
    DUMPOUT << head;
    if (sizeof...(Tail) > 0) DUMPOUT << ", ";
    dump_func(move(tail)...);
}

// chmax (更新「される」かもしれない値が前)
template <typename T, typename U, typename Comp = less<>> bool chmax(T &xmax, const U &x, Comp comp = {}) {
    if (comp(xmax, x)) {
        xmax = x;
        return true;
    }
    return false;
}

// chmin (更新「される」かもしれない値が前)
template <typename T, typename U, typename Comp = less<>> bool chmin(T &xmin, const U &x, Comp comp = {}) {
    if (comp(x, xmin)) {
        xmin = x;
        return true;
    }
    return false;
}

// ローカル用
#ifndef ONLINE_JUDGE
#define DEBUG_
#endif

#ifdef DEBUG_
#define DEB
#define dump(...)                                                                                                      \
    DUMPOUT << "  " << string(#__VA_ARGS__) << ": "                                                                    \
            << "[" << to_string(__LINE__) << ":" << __FUNCTION__ << "]" << endl                                        \
            << "    ",                                                                                                 \
        dump_func(__VA_ARGS__)
#else
#define DEB if (false)
#define dump(...)
#endif

#define VAR(type, ...)                                                                                                 \
    type __VA_ARGS__;                                                                                                  \
    cin >> __VA_ARGS__;

template <typename T> istream &operator,(istream &is, T &rhs) { return is >> rhs; }
template <typename T> ostream &operator,(ostream &os, const T &rhs) { return os << ' ' << rhs; }

struct AtCoderInitialize {
    static constexpr int IOS_PREC = 15;
    static constexpr bool AUTOFLUSH = false;
    AtCoderInitialize() {
        ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
        cout << fixed << setprecision(IOS_PREC);
        if (AUTOFLUSH) cout << unitbuf;
    }
} ATCODER_INITIALIZE;

void Yn(bool p) { cout << (p ? "Yes" : "No") << endl; }
void YN(bool p) { cout << (p ? "YES" : "NO") << endl; }

/* #endregion */

// #include <atcoder/all>
// using namespace atcoder;

// Problem
void solve() {
    VAR(ll, h, w, x); //
    if (x < (h - 1) + (w - 1)) {
        pprint(-1);
        return;
    }
    ll k = (h - 1) / 2;
    ll l = (w - 1) / 2;
    if (k % 2 == 1 && l % 2 == 1) {
        ll mi = min(h, w) - 1;
        ll ma = max(h, w) - 1;
        ll lb = mi + ma;
        ll ub = mi * (ma / 2) + ma + 2 * (mi - 2) / 2;
        // dump(lb, ub);
        ll d = x - lb;
        if (x > ub || d % 4 != 0) {
            pprint(-1);
            return;
        }
        bool swapped = false;
        if (h > w) {
            swap(h, w);
            swap(k, l);
            swapped = true;
        }
        assert(h <= w);
        ll step = d / 4;
        // dump(step);

        // k * wm 回以内なら，序盤の上下動で再現する
        ll wm = (l - 1) / 2;
        // dump(wm);
        vll updown(wm, 0);
        REP(i, 0, wm) {
            updown[i] = min(step, k);
            step -= updown[i];
            if (step == 0) break;
        }

        // 右の方で調整
        ll hm = (k - 1) / 2;
        vll leftright(hm, 0);
        REP(i, 0, hm) {
            leftright[i] = min(step, 1LL);
            step -= leftright[i];
            if (step == 0) break;
        }
        assert(step == 0);
        vc<string> tbl(h, string(w, '.'));
        // 通り道に '0' を付ける
        ll y = 0, x = 0;
        tbl[y][x] = 'o';
        REP(i, 0, wm) {
            REP(j, 0, updown[i]) {
                tbl[y][x + 1] = '#'; //
                tbl[++y][x] = 'o';   //
                tbl[y][x + 1] = '#'; //
                tbl[++y][x] = 'o';   //
            }
            REP(j, 2 * updown[i] + 1, h) tbl[j][x + 1] = '#'; //
            tbl[y][++x] = 'o';
            tbl[y][++x] = 'o';
            REP(j, 0, updown[i]) {
                tbl[y][x + 1] = '#'; //
                tbl[--y][x] = 'o';   //
                tbl[y][x + 1] = '#'; //
                tbl[--y][x] = 'o';   //
            }
            REP(j, 2 * updown[i] + 1, h) tbl[j][x + 1] = '#'; //
            tbl[y][++x] = 'o';
            tbl[y][++x] = 'o';
        }
        REP(i, 0, min(w - 1, 2LL)) {
            tbl[y + 1][x] = '#';
            tbl[y][++x] = 'o';
            tbl[y + 1][x] = '#';
            // dump(x);
        }
        REP(i, 0, min(h - 1, 2LL)) {
            tbl[++y][x] = 'o';
            tbl[y][x - 1] = '#'; //
        }
        tbl[y][x - 1] = '.'; //
        // dump(hm);
        REP(i, 0, hm) {
            REP(j, 0, leftright[i]) {
                tbl[y + 1][x] = '#'; //
                tbl[y][--x] = 'o';   //
                tbl[y + 1][x] = '#'; //
                tbl[y][--x] = 'o';   //
            }
            tbl[++y][x] = 'o';
            tbl[++y][x] = 'o';
            REP(j, 0, leftright[i]) {
                if (y + 1 < h) tbl[y + 1][x] = '#'; //
                tbl[y][++x] = 'o';                  //
                if (y + 1 < h) tbl[y + 1][x] = '#'; //
                tbl[y][++x] = 'o';                  //
            }
            if (!leftright[i]) {
                tbl[y - 1][x - 1] = '#';
                tbl[y - 1][x - 2] = '#';
                tbl[y - 1][x - 3] = '#';
                tbl[y + 1][x - 1] = '#';
                tbl[y + 1][x - 2] = '#';
                tbl[y + 1][x - 3] = '#';
            }
            tbl[++y][x] = 'o';
            tbl[++y][x] = 'o';
        }
        // REP(i, 0, h) pprint(tbl[i]);
        if (swapped) {
            vc<string> tbl2(w, string(h, ' '));
            REP(i, 0, h) REP(j, 0, w) tbl2[j][i] = tbl[i][j];
            swap(tbl, tbl2);
            swap(h, w);
        }
        // samitize
        REP(i, 0, h) REP(j, 0, w) {
            if (tbl[i][j] == 'o')
                tbl[i][j] = '.';
            else if ((i + 1) % 2 == 1 && (j + 1) % 2 == 1)
                tbl[i][j] = '.';
            // else
            //     tbl[i][j] = '#';
        }
        // dump
        REP(i, 0, h) pprint(tbl[i]);
        return;
    }

    if (k % 2 == 0 && l % 2 == 0) {
        ll lb = (h - 1) + (w - 1);
        ll ub = (h - 1) * (l + 1) + w;
        ll d = x - lb;
        if (x > ub || d % 4 != 0) {
            pprint(-1);
            return;
        }
        ll step = d / 4;

        // k * wm 回以内なら，序盤の上下動で再現する
        ll wm = l / 2;
        vll updown(wm, 0);
        REP(i, 0, wm) {
            updown[i] = min(step, k);
            step -= updown[i];
            if (step == 0) break;
        }

        vc<string> tbl(h, string(w, '.'));
        // 通り道に '0' を付ける
        ll y = 0, x = 0;
        tbl[y][x] = 'o';
        REP(i, 0, wm) {
            REP(j, 0, updown[i]) {
                tbl[y][x + 1] = '#'; //
                tbl[++y][x] = 'o';   //
                tbl[y][x + 1] = '#'; //
                tbl[++y][x] = 'o';   //
            }
            REP(j, 2 * updown[i] + 1, h) tbl[j][x + 1] = '#'; //
            tbl[y][++x] = 'o';
            tbl[y][++x] = 'o';
            REP(j, 0, updown[i]) {
                tbl[y][x + 1] = '#'; //
                tbl[--y][x] = 'o';   //
                tbl[y][x + 1] = '#'; //
                tbl[--y][x] = 'o';   //
            }
            REP(j, 2 * updown[i] + 1, h) tbl[j][x + 1] = '#'; //
            tbl[y][++x] = 'o';
            tbl[y][++x] = 'o';
        }
        REP(i, 0, 2) tbl[y][++x] = 'o';
        REP(i, 0, h - 1) tbl[++y][x] = 'o';

        // samitize
        REP(i, 0, h) REP(j, 0, w) {
            if (tbl[i][j] == 'o')
                tbl[i][j] = '.';
            else if ((i + 1) % 2 == 1 && (j + 1) % 2 == 1)
                tbl[i][j] = '.';
            // else
            //     tbl[i][j] = '#';
        }
        // dump
        REP(i, 0, h) pprint(tbl[i]);
        return;
    }

    // どっちか偶数．どっちか奇数．
    // l 偶数にしたい
    bool swapped = false;
    if (l % 2 == 1) {
        swap(h, w);
        swap(k, l);
        swapped = true;
    }
    assert(k % 2 == 1);
    assert(l % 2 == 0);

    {
        ll lb = (h - 1) + (w - 1);
        ll ub = (h - 1) * (l + 1) + w;
        ll d = x - lb;
        if (x > ub || d % 4 != 0) {
            pprint(-1);
            return;
        }
        ll step = d / 4;

        // k * wm 回以内なら，序盤の上下動で再現する
        ll wm = l / 2;
        vll updown(wm, 0);
        REP(i, 0, wm) {
            updown[i] = min(step, k);
            step -= updown[i];
            if (step == 0) break;
        }

        vc<string> tbl(h, string(w, '.'));
        // 通り道に '0' を付ける
        ll y = 0, x = 0;
        tbl[y][x] = 'o';
        REP(i, 0, wm) {
            REP(j, 0, updown[i]) {
                tbl[y][x + 1] = '#'; //
                tbl[++y][x] = 'o';   //
                tbl[y][x + 1] = '#'; //
                tbl[++y][x] = 'o';   //
            }
            REP(j, 2 * updown[i] + 1, h) tbl[j][x + 1] = '#'; //
            tbl[y][++x] = 'o';
            tbl[y][++x] = 'o';
            REP(j, 0, updown[i]) {
                tbl[y][x + 1] = '#'; //
                tbl[--y][x] = 'o';   //
                tbl[y][x + 1] = '#'; //
                tbl[--y][x] = 'o';   //
            }
            REP(j, 2 * updown[i] + 1, h) tbl[j][x + 1] = '#'; //
            tbl[y][++x] = 'o';
            tbl[y][++x] = 'o';
        }
        REP(i, 0, 2) tbl[y][++x] = 'o';
        REP(i, 0, h - 1) tbl[++y][x] = 'o';
        // dump
        // REP(i, 0, h) pprint(tbl[i]);
        if (swapped) {
            vc<string> tbl2(w, string(h, ' '));
            REP(i, 0, h) REP(j, 0, w) tbl2[j][i] = tbl[i][j];
            swap(tbl, tbl2);
            swap(h, w);
        }
        // samitize
        REP(i, 0, h) REP(j, 0, w) {
            if (tbl[i][j] == 'o')
                tbl[i][j] = '.';
            else if ((i + 1) % 2 == 1 && (j + 1) % 2 == 1)
                tbl[i][j] = '.';
            // else
            //     tbl[i][j] = '#';
        }
        // dump
        REP(i, 0, h) pprint(tbl[i]);
        return;
    }
}

// entry point
int main() {
    solve();
    return 0;
}