#include <atcoder/all>
using namespace atcoder;
#include <bits/stdc++.h>
using namespace std;
#include <boost/multiprecision/cpp_int.hpp>
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep2(i,a,b) for (int i = (int)(a); i < (int)(b); i++)
#define all(v) v.begin(),v.end()
#define inc(x,l,r) ((l)<=(x)&&(x)<(r)) 
#define Unique(x) sort(all(x)), x.erase(unique(all(x)), x.end())
#define pcnt __builtin_popcountll
typedef long long ll;
#define int ll
using ld = long double;
using vi = vector<int>;
using vs = vector<string>;
using P = pair<int,int>;
using vp = vector<P>;
using Bint = boost::multiprecision::cpp_int;
template<typename T1,typename T2> bool chmax(T1 &a, const T2 b) {if (a < b) {a = b; return true;} else return false; }
template<typename T1,typename T2> bool chmin(T1 &a, const T2 b) {if (a > b) {a = b; return true;} else return false; }
template<typename T> using priority_queue_greater = priority_queue<T, vector<T>, greater<T>>;
template<typename T1,typename T2> ostream &operator<< (ostream &os, const pair<T1,T2> &p){os << p.first <<" "<<p.second;return os;}
ostream &operator<< (ostream &os, const modint1000000007 &m){os << m.val();return os;}
istream &operator>> (istream &is, modint1000000007 &m){ll in;is>>in;m=in;return is;}
ostream &operator<< (ostream &os, const modint998244353 &m){os << m.val();return os;}
istream &operator>> (istream &is, modint998244353 &m){ll in;is>>in;m=in;return is;}
template<typename T> istream &operator>>(istream& is,vector<T> &v){for(T &in:v)is>>in;return is;}
template<class... T> void input(T&... a){(cin>> ... >> a);}
#ifdef LOCAL
template<typename T> ostream &operator<<(ostream &os,const vector<T> &v){os<<"\x1b[32m";rep(i,v.size())os<<v[i]<<(i+1!=v.size()?" ":"");os<<"\x1b[0m";return os;}
template<class T> int print(T& a){cout << "\x1b[32m"<< a<< '\n' << "\x1b[0m";return 0;}
template<class T,class... Ts> int print(const T&a, const Ts&... b){cout << "\x1b[32m" << a;(cout<<...<<(cout<<' ',b));cout<<'\n' << "\x1b[0m";return 0;}
#else
template<typename T> ostream &operator<<(ostream &os,const vector<T> &v){rep(i,v.size())os<<v[i]<<(i+1!=v.size()?" ":"");return os;}
template<class T> int print(T& a){cout << a<< '\n';return 0;}
template<class T,class... Ts> int print(const T&a, const Ts&... b){cout << a;(cout<<...<<(cout<<' ',b));cout<<'\n';return 0;}
#endif
#define VI(v,n) vi v(n); input(v)
#define INT(...) int __VA_ARGS__; input(__VA_ARGS__)
#define STR(...) string __VA_ARGS__; input(__VA_ARGS__)
#define CHAR(...) char __VA_ARGS__; input(__VA_ARGS__)
int sign(ll x){return x>0?1:x<0?-1:0;}
ll ceil(ll x,ll y){assert(y!=0);if(sign(x)==sign(y))return (x+y-1)/y;return -((-x/y));}
ll floor(ll x,ll y){assert(y!=0);if(sign(x)==sign(y))return x/y;if(y<0)x*=-1,y*=-1;return x/y-(x%y<0);}
ll abs(ll x,ll y){return abs(x-y);}
ll bit(int n){return 1ll<<n;}
template<class T> bool ins(string s,T t){return s.find(t)!=string::npos;}
P operator+ (const P &p, const P &q){ return P{p.first+q.first,p.second+q.second};}
P operator- (const P &p, const P &q){ return P{p.first-q.first,p.second-q.second};}
int yesno(bool ok,string y="Yes",string n="No"){ cout<<(ok?y:n)<<endl;return 0;}
int YESNO(bool ok,string y="YES",string n="NO"){ cout<<(ok?y:n)<<endl;return 0;}
int di[]={-1,0,1,0,-1,-1,1,1};
int dj[]={0,1,0,-1,-1,1,-1,1};
const ll INF = 8e18;
//using mint = modint1000000007;
// using mint = modint998244353;
//mint stom(const string &s,int b=10){mint res = 0;for(auto c:s)res *= b,res += c-'0';return res;}
template<typename F>
pair<vi,vi> loopfind(F &&nxt,int s=0){
    int fast = s;
    int slow = s;
    while(1){
        fast = nxt(nxt(fast));
        slow = nxt(slow);
        if(fast == slow)break;
    }
    fast = s;
    while(1){
        fast = nxt(fast);
        slow = nxt(slow);
        if(fast == slow)break;
    }
    int loopstart = fast;
    vi tail;
    tail.push_back(s);
    int i = nxt(s);
    while(i!=loopstart){
        tail.push_back(i);
        i = nxt(i);
    }
    vi loop;
    loop.push_back(loopstart);
    i = nxt(loopstart);
    while(i!=loopstart){
        loop.push_back(i);
        i = nxt(i);
    }
 
    return {tail,loop};
}
signed main() {
    cin.tie(0);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(20);

    INT(h,w,k);
    using mint = modint;
    mint::set_mod(2);
    int n = h*w*4;
    vp dij = {{1,1},{1,-1},{-1,1},{-1,-1}};
    auto D = [](int di,int dj){
        if(di==1&&dj==1)return 0;
        if(di==1&&dj==-1)return 1;
        if(di==-1&&dj==1)return 2;
        if(di==-1&&dj==-1)return 3;
        assert(0);
    };
    auto f = [&](int i,int j,int d){
        return (i*w+j)+d*h*w;
    };
    vi a(n);
    rep(i,h)rep(j,w)rep(d,4){
        auto [di,dj] = dij[d];
        int ni = i+di;
        int nj = j+dj;
        if(!inc(ni,0,h))ni = i,di *= -1;
        if(!inc(nj,0,w))nj = j,dj *= -1;
        a[f(i,j,d)] = f(ni,nj,D(di,dj));
        // print(i,j,d,f(i,j,d),ni,nj,D(di,dj),f(ni,nj,D(di,dj)));
    }
    auto [tail,loop] = loopfind([&](int i){return a[i];});
    auto g = [&](int f){
        f %= h*w;
        return P{f/w,f%w};
    };
    vector res(h,vi(w));
    if(tail.size()){
        int tz = tail.size();
        int r = min(k,tz);
        rep(id,r){
            auto [i,j] = g(tail[id]);
            res[i][j] ^=1;
        }
        k -= r;
    }
    if(k){
        auto lz = loop.size();
        int l = k/lz;
        int r = k%lz;
        if(l&1)for(auto f:loop){
            auto [i,j] = g(f);
            res[i][j] ^= 1;
        }
        rep(id,r){
            auto [i,j] = g(loop[id]);
            res[i][j] ^= 1;
        }
    }
    rep(i,h){
        string s(w,'.');
        rep(j,w)if(res[i][j])s[j] = '#';
        print(s);
    }
    return 0;
}