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

// #define int long long

typedef pair<int, int> pii;
typedef long long LL;
typedef unsigned long long uLL;

const int inf32 = 1e9;
const LL inf64 = 1e18;

int main()
{
    cin.tie(0); cout.tie(0);
    ios::sync_with_stdio(0);

    int T = 1;
    cin >> T;
    while (T--) {
        int n;
        cin >> n;
        string a, b;
        cin >> a >> b;
        vector<string> ans(10, string(n, '.'));

        int cnta0 = 0, cnta1 = 0, cntb0 = 0, cntb1 = 0;
        int ffa = 0, ffb = 0;
        for (int i = 0; i < n; i++) {
            if (a[i] == '.') ++cnta0;
                else ++cnta1;
            if (b[i] == '.') ++cntb0;
                else ++cntb1;
        }
        if (!cnta0 || !cnta1) ffa = 1;
        if (!cntb0 || !cntb1) ffb = 1;

        if (ffa || ffb) {
            if (ffa && ffb) {
                cout << "YES\n";
                for (int i = 1; i <= 6; i++)
                    cout << a << "\n";
                cout << b << "\n";
            } else {
                cout << "NO\n";
            }
            continue;
        }

        ans[1] = a, ans[7] = b;
        for (int i = 0; i < n; i++) {
            ans[2][i] = ans[1][i] == '.' ? '#' : '.';
            ans[6][i] = ans[7][i] == '.' ? '#' : '.';
        }
        if (ans[2][0] == '#' && ans[2][1] == '#') ans[2][0] = '.';
        if (ans[6][0] == '#' && ans[6][1] == '#') ans[6][0] = '.';

        int fir = 0;
        for (int i = 0; i <= n; i++) {
            if (ans[2][i] == '#') {fir = i; break;}
        }
        for (int i = 1; i < fir; i++) ans[3][i] = '#';
        if (fir <= 1) ans[3][0] = '#';
        
        fir = 0;
        for (int i = 0; i <= n; i++) {
            if (ans[6][i] == '#') {fir = i; break;}
        }
        for (int i = 1; i < fir; i++) ans[5][i] = '#';
        if (fir <= 1) ans[5][0] = '#';
        ans[4][0] = '#';

        cout << "YES\n";
        for (int i = 1; i <= 7; i++)
            cout << ans[i] << "\n";
    }


    return 0;
}