#include<bits/stdc++.h>
using namespace std;
#define int long long
#define endl '\n'
#define pii pair<int, int>
void solve();

signed main()
{
	ios::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	int T = 1;
	cin >> T;
	while (T--)solve();
	return 0;
}
const int mod = 1e9 + 7;

void solve() {
	int n;
	cin >> n;
	vector<string>s(n + 1);
	vector<vector<int>>a(n + 1, vector<int>(26));
	for (int i = 1; i <= n; i++) {
		cin >> s[i];
		for (auto c : s[i]) {
			a[i][c - 'a']++;
		}
	}
	priority_queue<pii>q;
	const int m = 26;
	vector<vector<int>>lim(n + 3, vector<int>(m));
	int cnt = 0;
	q.push({ s[n].size(),0 });
	//vector<int>t(m);
	lim[cnt++] = a[n];
	for (int i = n - 1; i >= 1; i--) {
		int sz = s[i].size();
		while (q.size()) {
			auto& it = q.top();
			int r = it.first, tmp = it.second;
			if (r < sz) {
				break;
			}
			q.pop();
			auto& qu = lim[tmp];
			int di = r / sz;
			for (int j = 0; j < m; j++) {
				qu[j] -= a[i][j] * di;
				if (qu[j] < 0) {
					cout << "NO\n";
					return;
				}
			}
			if (r % sz != 0)q.push({ r % sz,tmp });
		}
		if (i != 1) {
			q.push({ sz,cnt });
			lim[cnt++] = a[i];
		}
	}
	int sz = s[1].size();
	vector<int>pre = a[1];
	q.push({ 0,n + 2 });
	//cout << q.size() << endl;
	for (int t = sz - 1; t >= 0; t--) {
		while (q.size() && q.top().first == t) {
			int r = q.top().first, tmp = q.top().second;
			q.pop();
			int x = t;
			//cout << "r== " << r << endl;
			for (int j = 0; j < m; j++) {
				//cout << lim[tmp][j] << ' ';
				pre[j] -= lim[tmp][j];
				if (pre[j] < 0) {
					cout << "NO\n";
					return;
				}
				while (pre[j]--) {
					if (x >= s[1].size()) {
						cout << "NO\n";
						return;
					}
					s[1][x++] = j + 'a';
				}
			}
			//cout << endl;
			pre = lim[tmp];
		}
	}
	//cout << q.size() << endl;
	//cout << q.top().first << endl;
	cout << "YES\n";
	cout << s[1] << endl;
	for (int i = 2; i <= n; i++) {
		for (int j = 0; j < s[i].size(); j++) {
			s[i][j] = s[i - 1][j % s[i - 1].size()];
		}
		cout << s[i] << endl;
	}
}