#include <bits/stdc++.h>
#define fi first 
#define se second
using namespace std;
#define pb push_back
#define ls (u << 1)
#define rs (u << 1 | 1)

typedef long long LL;
typedef pair<int, int> PII;

// #define debug(args...) {}
#define debug(args...) { \
     string _s = #args; replace(_s.begin(), _s.end(), ',', ' '); \
     stringstream _ss(_s); istream_iterator<string> _it(_ss); err(_it, args); cout << '\n';}
void err(istream_iterator<string> it){}
template<typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
    cout << *it << " = " << a << ' ';
    err(++it, args...);
}

void solve() {
    int n; cin >> n;
    int ca = 0, cb = 0;
    string s; cin >> s;
    string t; cin >> t;
    for (auto ch : s) ca += ch == '.';
    for (auto ch : t) cb += ch == '.';
    if (!ca && !cb) {
        cout << "Yes\n";
        for (int i = 0; i < 7; i++) {
            cout << s << "\n";
        }
        return ;
    }
    else if (!ca || !cb) {
        cout << "No\n";
        return ;
    }
    
    int cnt = 0;
    for (int i = 0; i < n; i++) cnt += s[i] == t[i];
    if (!cnt) {
        cout << "Yes\n";
        for (int i = 0; i < 6; i++) cout << s << "\n";
        cout << t << "\n";
        return ;
    }
    
    string ss = s, tt = t;
    for (auto &ch : ss) ch = (ch == '.') ? '#' : '.';
    for (auto &ch : tt) ch = (ch == '.') ? '#' : '.';
    
    vector<string> ans(7);
    ans[0] = s; ans[6] = t;
    ans[1] = ss; ans[5] = tt;
    ans[2] = ans[3] = ans[4] = s;
    cnt = 0;
    for (int i = 0; i < n; i++) cnt += ss[i] == '.' && tt[i] == '.';
    int lst = 1, nxt = 5;
    if (!cnt) ans[++lst] = s;
    for (int i = 0; i < n; i++) {
        if (ans[lst][i] != '.' || ans[nxt][i] != '.') continue;
        int j = i;
        while (j < n && ans[lst][j] == '.' && ans[nxt][j] == '.') j++;
        int ok1 = (i && ans[lst][i - 1] == '#') || (j < n && ans[lst][j] == '#');
        int ok2 = (i && ans[nxt][i - 1] == '#') || (j < n && ans[nxt][j] == '#');
        // debug(i, j, ok1, ok2, nxt);
        if (ok1 && !ok2) {
            for (int b = 0; b < n; b++) ans[nxt - 1][b] = '.';
            for (int b = j; b < n; b++) {
                if (ans[nxt][b] == '#') break;
                ans[nxt - 1][b] = '#';
            }
            for (int b = i - 1; b >= 0; b--) {
                if (ans[nxt][b] == '#') break;
                ans[nxt - 1][b] = '#';
            }
            nxt--;
        }
        else if (!ok1 && ok2) {
            for (int b = 0; b < n; b++) ans[lst + 1][b] = '.';
            for (int b = j; b < n; b++) {
                if (ans[lst][b] == '#') break;
                ans[lst + 1][b] = '#';
            }
            for (int b = i - 1; b >= 0; b--) {
                if (ans[lst][b] == '#') break;
                ans[lst + 1][b] = '#';
            }
            lst++;
        }
        for (int a = lst + 1; a < nxt; a++) {
            for (int b = 0; b < n; b++) {
                if (ans[lst][b] == '.' && ans[nxt][b] == '.') ans[a][b] = '#';
                else ans[a][b] = '.';
            }
        }
        break;
    }
    cout << "Yes\n";
    for (int i = 0; i < 7; i++) cout << ans[i] << "\n";
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    int tt = 1; cin >> tt;
    while (tt--) solve();
    return 0;
}
/*
g++ std.cpp -Wall --extra -o std && ./std < in.txt > out.txt
*/