#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define all(p) p.begin(),p.end()
#define rep(i,a,b) for(int i=(int)a;i<(int)b;i++)

int main(){
	ll H,W,K;
	cin>>H>>W>>K;
	K%=(4ll*H*W);
	vector S(H,vector<bool>(W));
	int x=0,y=0,dx=1,dy=1;
	rep(rp,0,K){
		S[x][y]=!S[x][y];
		if(x+dx==-1||x+dx==H) dx*=-1;
		else x+=dx;
		if(y+dy==-1||y+dy==W) dy*=-1;
		else y+=dy;		
	}
	rep(i,0,H){
		rep(j,0,W) cout<<(S[i][j]?"#":".");
		cout<<"\n";
	}
}