#include <bits/stdc++.h>
using namespace std;
using i64 = long long;

void solve() {
    int n;
    cin >> n;
    string x, y;
    cin >> x >> y;
    vector<int> a(n), b(n);
    for (int i = 0; i < n; i++) {
        a[i] = x[i] == '#';
        b[i] = y[i] == '#';
    }
    int aa = accumulate(a.begin(), a.end(), 0);
    int bb = accumulate(b.begin(), b.end(), 0);
    if (aa == n && bb == n) {
        cout << "YES\n";
        for (int i = 0; i < 7; i++) {
            cout << x << "\n";
        }
        return;
    } 
    if (aa == n || bb == n) {
        cout << "NO\n";
        return;
    }
    cout << "YES\n";
    vector<vector<int>> adj(7, vector<int>(n));
    adj[0] = a, adj[6] = b;

    for (int i = 0; i < n; i++) {
        adj[1][i] = adj[0][i] ^ 1;
        adj[5][i] = adj[6][i] ^ 1;
    }

    auto print = [&]() {
        for (int i = 0; i < 7; i++) {
            for (int j = 0; j < n; j++) {
                cout << (adj[i][j] ? '#' : '.');
            }
            cout << "\n";
        }
    };

    int s = -1, t = -1;
    for (int i = 0; i < n; i++) {
        if (adj[1][i] == 0 && (i + 1 < n && adj[1][i + 1] == 1 || i - 1 >= 0 && adj[1][i - 1] == 1)) s = i;
        if (adj[5][i] == 0 && (i + 1 < n && adj[5][i + 1] == 1 || i - 1 >= 0 && adj[5][i - 1] == 1)) t = i;
    }
    adj[2][s] = adj[4][t] = 1;
    if (s == t) {
        adj[3][s] = 1;
    } else if (abs(s - t) > 1) {
        for (int i = min(s, t) + 1; i < max(s, t); i++) {
            adj[3][i] = 1;
        }
    } else {
        adj[3][s] = 1;
    }
    print();
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    int t = 1;
    cin >> t;

    while (t--) {
        solve();
    }

    return 0;
}