1950B

#include <bits/stdc++.h>
using namespace std;
int n;

int main()
{
    int t;
    cin>>t;
    
    while(t--){
        cin>>n;
        int t=n;
        for(int i=0;i<2*n;i++){
            for(int j=0;j<2*n;j++){
                if(i/2%2!=j/2%2) cout<<".";
                else cout<<"#";
            }
            cout<<endl;
        }
       // cout<<endl;
        
    }
    return 0;
}

if(i / 2 % 2 != j / 2 % 2) cout<<".";

#include<iostream>
using namespace std;
int left;
int a,b,c;
int main(){
	int n,m;
	cin>>m;
	while(m--){
	
	cin>>n;
	for(int i=1;i<=2*n;i++){
		for(int j=1;j<=2*n;j++){
			if(((i+1)/2)%2==1&&((j+1)/2)%2==1){
				cout<<"#";
			}
			if(((i+1)/2)%2==0&&((j+1)/2)%2==1){
				cout<<".";
			}
			if(((i+1)/2)%2==1&&((j+1)/2)%2==0){
				cout<<".";
			}
			if(((i+1)/2)%2==0&&((j+1)/2)%2==0){
				cout<<"#";
			}
		}
		cout<<endl;
	}
}
}