#include<bits/stdc++.h>
using namespace std;
#define int long long
using namespace std;
const int N = 100000 + 10;
const int M = 3000 + 10;
void solve() {
	int n;
	string s1, s2;
	cin >> n;
	cin >> s1 >> s2;
	int c1 = 0, c2 = 0;
	for (int i = 0; i < n; i++) {
		if (s1[i] == '#')c1++;
		if (s2[i] == '#')c2++;
	}
	if (c1 == n || c2 == n) {
		if (c1 == n && c2 == n) {
			cout << "Yes" << endl;
			for (int i = 1; i <= 7; i++)cout << s1 << endl;
		}
		else cout << "No" << endl;
	}
	else {
		cout << "Yes" << endl;
		c1 = c2 = 1;
		queue<string>ans;
		ans.push(s1);
		for (int i = 0; i <n; i++) {
			if (s1[i] == '#')s1[i] = '.';
			else s1[i] = '#';
			if (s2[i] == '#')s2[i] = '.';
			else s2[i] = '#';
		}
		ans.push(s1);
		for (int i = 0; i < n; i++) {
			if (s1[i] == '.' && (i + 1 < n && s1[i + 1] == '#' || i - 1 >= 0 && s1[i - 1] == '#'))c1 = i;
			if (s2[i] == '.' && (i + 1 < n && s2[i + 1] == '#' || i - 1 >= 0 && s2[i - 1] == '#'))c2 = i;
		}
		for (int i = 0; i < n; i++) s1[i] = '.';
		s1[c1] = '#';
		ans.push(s1);
		s1[c1] = '.';
		int l, r;
		l = min(c1, c2);
		r = max(c1, c2);
		if (r - l <= 1) {
			s1[c2] = '#';
			ans.push(s1);
			s1[c2] = '.';
		}
		else {
			for (int i = l + 1; i < r; i++)s1[i] = '#';
			ans.push(s1);
			for (int i = l + 1; i < r; i++)s1[i] = '.';
		}
		s1[c2] = '#';
		ans.push(s1);
		ans.push(s2);
		for (int i = 0; i < n; i++) {
			if (s1[i] == '#')s1[i] = '.';
			else s1[i] = '#';
			if (s2[i] == '#')s2[i] = '.';
			else s2[i] = '#';
		}
		ans.push(s2);
		while (!ans.empty()) {
			cout << ans.front() << endl;
			ans.pop();
		}
	}
}
signed main() {
	std::ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int t = 1;
	cin >> t;
	while (t--) {
		solve();
	}
}
/*
4
4
#..#
.##.
5
##.#.
.#.##
6
######
.####.
27
.######.######.####.#.#####
.####...####..#.......#####
*/