#include <bits/stdc++.h>

using namespace std;

#define ar array
#define ll long long
typedef int uci;
#define int long long
#define F first
#define S second
typedef complex<double> cd;

seed_seq seq{
    (uint64_t) chrono::duration_cast<chrono::nanoseconds>(chrono::high_resolution_clock::now().time_since_epoch()).count(),
    (uint64_t) __builtin_ia32_rdtsc(),
    (uint64_t) (uintptr_t) make_unique<char>().get()
};
mt19937 rng(seq);
// mt19937_64 lrng(seq);

struct debugger{
    template <typename T>
    debugger& operator<<(T &a){
        #ifdef DEBUG
            cerr << a;
        #endif
        return *this;
    }
    template <typename T>
    debugger& operator<<(T &&a){
        #ifdef DEBUG
            cerr << a;
        #endif
        return *this;
    }
} deb;

const double PI = acos(-1.0);
const int MAX_N = 1e5 + 1;
const int MOD = 1e9 + 7;
const int INF = 1e9;
const ll LINF = 1e18;

//! function insert

//THINK FIRST, CODE SECOND
//DON'T GET STUCK ON ONE STRATEGY
//CALM DOWNNN FOR ONCE IN YOUR LIFE
//REDUCE
//COUGH E??!?!?!! O.O
//uwu i see you ryan
int n;
bool cando(int i, int j){
    return i >= 0 && i < n && j >= 0 && j < n;
}
void markbad(int i, int j, vector<vector<bool>> &good){
    for(int o = -1; o <= 1; ++o){
        for(int k = -1; k <= 1; ++k){
            if(cando(i+o, j+k))
                good[i+o][j+k] = false;
        }
    }
}

int wayone(vector<string> &a){
    int added{};
    for(int i{}; i < n; i += 3){
        if(i+1 >= n){
            for(int j{}; j < n; j += 3){
                if(j+1 >= n)
                    break;
                a[i][j] = a[i][j+1] = '#';
                added++;
            }
            break;
        }
        for(int j{}; j < n; j += 2){
            a[i][j] = a[i+1][j] = '#';
            added++;
        }
    }

    return added;
}

int waytwo(vector<string> &a){
    int added{};
    int x = 0, y = 0;
    vector<ar<int, 2>> ds{{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
    vector<vector<bool>> good(n, vector<bool>(n, true));
    int dind{};
    int upb = 0, lowb = n-1, leftb = 1, rightb = n-1;
    for(int i{}; i < n*n; ++i){
        if(dind == 0 && x == lowb){
            dind++;
            lowb--;
        }
        if(dind == 1 && y == rightb){
            dind++;
            rightb--;
        }
        if(dind == 2 && x == upb){
            dind++;
            upb++;
        }
        if(dind == 3 && y == leftb){
            dind = 0;
            leftb++;
        }
        int nex, ney;
        nex = x+ds[dind][0];
        ney = y+ds[dind][1];

        if(good[x][y] && good[nex][ney]){
            a[x][y] = '#';
            a[nex][ney] = '#';
            added++;
            markbad(x, y, good);
            markbad(nex, ney, good);
        }
        x = nex, y = ney;
    }
    return added;
}

int waythree(vector<string> &a, int l, int r, int u, int d){
    int si = r-l+1;
    if(si <= 1)
        return 0;
    if(si == 2){
        a[l][l] = a[l+1][l] = '#';
        return 1;
    }
    if(si == 3){
        a[l][l] = a[l+1][l] = '#';
        a[l][l+2] = a[l+1][l+2] = '#';
        return 2;
    }

    int added{};
    for(int i = l; i < r-2; i += 2){
        a[u][i] = a[u+1][i] = '#';
        added++;
    }
    for(int i = u; i < d-2; i += 2){
        a[i][r] = a[i][r-1] = '#';
        added++;
    }
    for(int i = r; i > l+2; i -= 2){
        a[d][i] = a[d-1][i] = '#';
        added++;
    }
    for(int i = d; i > u+2; i -= 2){
        a[i][l] = a[i][l+1] = '#';
        added++;
    }
    added += waythree(a, l+3, r-3, u+3, d-3);
    return added;
}

void solve() {
    cin >> n;
    vector<string> a(n, string(n, '.'));
    vector<string> b(n, string(n, '.'));
    vector<string> c(n, string(n, '.'));
    vector<string> d(n, string(n, '.'));

    int one = wayone(a);
    int two = waytwo(b);
    int three = waythree(c, 0, n-1, 0, n-1);
    int four = 0;
    if(n%2){
        four = waythree(d, 0, n/2-1, 0, n/2-1) + waythree(d, n/2+1, n-1, 0, n/2-1) + waythree(d, 0, n/2-1, n/2+1, n-1) + waythree(d, n/2+1, n-1, n/2+1, n-1);
    }

    if(one >= two && one >= three && one >= four)
        for(auto &t : a)
            cout << t << '\n';
    else if(two >= one && two >= three && two >= four)
        for(auto &t : b)
            cout << t << '\n';
    else if(three >= one && three >= two && three >= four)
        for(auto &t : c)
            cout << t << '\n';
    else
        for(auto &t : d)
            cout << t << '\n';
}

uci main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    // freopen("input.txt", "r", stdin);
    // freopen("output.txt", "w", stdout);

    int tc; cin >> tc;
    for (int t = 1; t <= tc; t++) {
        // cout << "Case #" << t  << ": ";
        solve();
    }
}

/*
    random number generator stuff
    num = rng(); gives integer number
    num = uniform_int_distribution<int>(a, b)(rng); -> bounds [a, b]
    num = uniform_real_distribution<double>(a, b)(rng); -> bounds [a, b)
    can also instantiate distributions and call on generator:
    uniform_int_distribution<int> thing(a, b);
    num = thing(rng);
*/
// struct custom_hash {
//     static uint64_t splitmix64(uint64_t x) {
//         // http://xorshift.di.unimi.it/splitmix64.c
//         x += 0x9e3779b97f4a7c15;
//         x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
//         x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
//         return x ^ (x >> 31);
//     }
//     size_t operator()(uint64_t x) const {
//         static const uint64_t FIXED_RANDOM = lrng();
//         return splitmix64(x + FIXED_RANDOM);
//     }
// };