#include <bits/stdc++.h>
#define int long long
#define pb push_back
using namespace std;
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int T;
cin >> T;
while(T--){
int a;
cin >> a;
for(int ind = 0 ;ind < 2 * a ;ind++){
for(int jind = 0 ; jind < a;jind++){
int b =(ind / 2 + jind) % 2;
if(b == 0){
cout << "##";
} else{
cout << "..";
}
}
cout << '\n';
}
}
}
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