#include <iostream>
#include <cstdio>
using namespace std;

int n,m;

int main()
{
int i,j;
    freopen("concentric_squares.in","rt",stdin);
     freopen("concentric_squares.out","wt",stdout);
    cin>>n;
    m = 1+4*(n-1);
    int br = 0,p=0;
    for(i=1;i<=m;i++){
       // cout<<"#";
       for(j=1;j<=br;j++){
            cout<<"#.";
       }
       if(p==1 && i%2==0)cout<<".";
       else
        if(br==n-1 && i%2 == 0)cout<<".";
       else
        cout<<"#";
        if(i%2 == 1){
          //  cout<<"#";
            for(j=1;j<=m-4*br-2;j++)cout<<"#";
        }
        else{
              //  cout<<endl<<br<<" "<<m-4*br-2<<endl;
            for(j=1;j<=m-4*br-2;j++)cout<<".";
        }
        //if(br != n-1)cout<<"#";

        if(p==1 && i%2==0)cout<<".";
        else
        if(br != n-1)
            cout<<"#";
        for(j=1;j<=br;j++){
            cout<<".#";
       }
       cout<<endl;
      // cout<<"#"<<endl;
        if(i%2 == 0 && p == 0)br++;
        if(i%2 == 0 && p == 1)br--;
        if(br == n){
            p=1;
            br-=2;
        }
    }

    return  0;
}