#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using ll = long long;
#define rep(i,n) for(int i=0;i<(int)(n);i++)
using mint = atcoder::modint998244353;

int main(){
	int h,w;
	cin>>h>>w;
	ll k;
	cin>>k;
	k%=8*h*w;
	vector<vector<int>> ans(h,vector<int>(w,0));
	auto isok=[&](int i,int j){
		return 0<=i&&i<h&&0<=j&&j<w;
	};
	int nx=0,ny=0;
	int dx=1,dy=1;
	rep(lp,k){
		ans.at(nx).at(ny)^=1;
		if(isok(nx+dx,ny)) nx+=dx;
		else dx*=-1;
		if(isok(nx,ny+dy)) ny+=dy;
		else dy*=-1;
	}
	rep(i,h){
		rep(j,w) cout<<(ans.at(i).at(j)?'#':'.');
		cout<<"\n";
	}
}