#include <bits/stdc++.h>
using namespace std;
// #define int long long
#define ll long long
#define double long double
#define endl '\n'
#define all(a) a.begin(), a.end()
#define pb push_back
#define x first
#define y second
#define debug(_x) cout << #_x << '=' << _x << endl
typedef pair<int, int> PII;
using i64 = long long;
const int mod = 1e9 + 7;
const int N = 2e5 + 10;

void solve()
{
    int n;
    cin >> n;
    string a, b;
    cin >> a >> b;
    int cnt1 = 0, cnt2 = 0;
    for (int i = 0; i < n; i++)
    {
        if (a[i] == '#')
            cnt1++;
        if (b[i] == '#')
            cnt2++;
    }
    if (cnt1 == n && cnt2 == n)
    {
        cout << "YES\n";
        for (int i = 1; i <= 7; i++)
        {
            for (int j = 1; j <= n; j++)
                cout << '#';
            cout << endl;
        }
        return;
    }
    else if (cnt1 == n || cnt2 == n)
    {
        cout << "NO\n";
        return;
    }
    int pos1 = -1, pos2 = -1;
    for (int i = 0; i < n; i++)
    {
        if (a[i] == '#' && ((i - 1 >= 0 && a[i - 1] == '.') || (i + 1 < n && a[i + 1] == '.')))
        {
            pos1 = i;
            break;
        }
    }
    for (int i = 0; i < n; i++)
    {
        if (b[i] == '#' && ((i - 1 >= 0 && b[i - 1] == '.') || (i + 1 < n && b[i + 1] == '.')))
        {
            pos2 = i;
            break;
        }
    }
    cout << "YES\n";
    cout << a << endl;
    for (int i = 0; i < n; i++)
        cout << char('.' + '#' - a[i]);
    cout << endl;
    for (int i = 1; i <= n; i++)
    {
        if (i != pos1 + 1)
            cout << '.';
        else
            cout << '#';
    }
    cout << endl;
    int start = min(pos1, pos2) + 1, end = max(pos1, pos2) + 1;
    if (start == end || start + 1 == end)
    {
        for (int i = 1; i <= end - 1; i++)
            cout << '.';
        cout << '#';
        for (int i = end + 1; i <= n; i++)
            cout << '.';
    }
    else
    {
        for (int i = 1; i <= start; i++)
            cout << '.';
        for (int i = start + 1; i < end; i++)
            cout << '#';
        for (int i = end; i <= n; i++)
            cout << '.';
    }
    cout << endl;
    for (int i = 1; i <= n; i++)
    {
        if (i != pos2 + 1)
            cout << '.';
        else
            cout << '#';
    }
    cout << endl;
    for (int i = 0; i < n; i++)
        cout << (char)('.' + '#' - b[i]);
    cout << endl;
    cout << b << endl;
}

int main()
{
    /*ios::sync_with_stdio(false);
    cin.tie(nullptr);*/
    int _ = 1;
    cin >> _;

    while (_--)
        solve();

    return 0;
}