#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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