#ifndef LOCAL
#define FAST_IO
#endif

// ============
#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <cmath>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

#define OVERRIDE(a, b, c, d, ...) d
#define REP2(i, n) for (i32 i = 0; i < (i32)(n); ++i)
#define REP3(i, m, n) for (i32 i = (i32)(m); i < (i32)(n); ++i)
#define REP(...) OVERRIDE(__VA_ARGS__, REP3, REP2)(__VA_ARGS__)
#define PER(i, n) for (i32 i = (i32)(n) - 1; i >= 0; --i)
#define ALL(x) begin(x), end(x)

using namespace std;

using u32 = unsigned int;
using u64 = unsigned long long;
using i32 = signed int;
using i64 = signed long long;
using f64 = double;
using f80 = long double;

template <typename T>
using Vec = vector<T>;

template <typename T>
bool chmin(T &x, const T &y) {
    if (x > y) {
        x = y;
        return true;
    }
    return false;
}
template <typename T>
bool chmax(T &x, const T &y) {
    if (x < y) {
        x = y;
        return true;
    }
    return false;
}

#ifdef INT128

using u128 = __uint128_t;
using i128 = __int128_t;

istream &operator>>(istream &is, i128 &x) {
    i64 v;
    is >> v;
    x = v;
    return is;
}
ostream &operator<<(ostream &os, i128 x) {
    os << (i64)x;
    return os;
}
istream &operator>>(istream &is, u128 &x) {
    u64 v;
    is >> v;
    x = v;
    return is;
}
ostream &operator<<(ostream &os, u128 x) {
    os << (u64)x;
    return os;
}

#endif

[[maybe_unused]] constexpr i32 INF = 1000000100;
[[maybe_unused]] constexpr i64 INF64 = 3000000000000000100;
struct SetUpIO {
    SetUpIO() {
#ifdef FAST_IO
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
#endif
        cout << fixed << setprecision(15);
    }
} set_up_io;
// ============

#ifdef DEBUGF
#else
#define DBG(x) (void)0
#endif

int main() {
    i32 h, w;
    i64 k;
    cin >> h >> w >> k;
    
    map<tuple<i32, i32, i32, i32>, i32> memo;
    tuple<i32, i32, i32, i32> cur(0, 0, 1, 1);
    memo[cur] = 0;
    i32 turn = 0;
    while (true) {
        ++turn;
        auto [x, y, dx, dy] = cur;
        if (0 <= x + dx && x + dx < h) {
            x += dx;
        } else {
            dx *= -1;
        }
        if (0 <= y + dy && y + dy < w) {
            y += dy;
        } else {
            dy *= -1;
        }
        cur = make_tuple(x, y, dx, dy);
        if (memo.count(cur)) {
            break;
        } else {
            memo[cur] = turn;
        }
    }
    i32 len = turn - memo[cur];
    i32 off = memo[cur];
    Vec<Vec<i32>> grid(h, Vec<i32>(w, 0));
    if (k < off) {
        for (auto [state, turn] : memo) {
            if (turn < k) {
                auto [x, y, dx, dy] = state;
                grid[x][y] ^= 1;
            }
        }
    } else {
        for (auto [state, turn] : memo) {
            auto [x, y, dx, dy] = state;
            if (turn < off) {
                grid[x][y] ^= 1;
            } else {
                turn -= off;
                i64 cnt = turn / len;
                if (turn % len < (k - off) % len) {
                    ++cnt;
                }
                grid[x][y] ^= cnt % 2;
            }
        }
    }
    REP(i, h) REP(j, w) {
        if (grid[i][j] == 0) {
            cout << '.';
        } else {
            cout << '#';
        }
        if (j == w - 1) {
            cout << '\n';
        }
    }
}