#include<iostream>
#include<algorithm>
#include<vector>
#include<queue>
#include<cassert>
//#include<atcoder/modint>
using namespace std;
//using mint=atcoder::modint998244353;
int H,W;
long K;
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cin>>H>>W>>K;
	vector<vector<vector<long> > >vis(H,vector<vector<long> >(W,vector<long>(4,-1)));
	vector<vector<int> >col(H,vector<int>(W,0));
	int x=0,y=0,dir=0;
	while(K>0)
	{
		if(vis[x][y][dir]!=-1)
		{
			long d=vis[x][y][dir]-K;
			d*=2;
			K%=d;
		}
		vis[x][y][dir]=K;
		col[x][y]=1-col[x][y];
		{
			int tx=x;
			if(dir%2==0)tx++;
			else tx--;
			if(tx>=0&&tx<H)x=tx;
			else dir^=1;
		}
		{
			int ty=y;
			if(dir/2==0)ty++;
			else ty--;
			if(ty>=0&&ty<W)y=ty;
			else dir^=2;
		}
		K--;
	}
	for(int i=0;i<H;i++)
	{
		for(int j=0;j<W;j++)cout<<(col[i][j]==0?'.':'#');
		cout<<"\n";
	}
}