#include <bits/stdc++.h>
#define x first
#define y second
using namespace std;
using ll=long long;
using pii=pair<int,int>;
using vi=vector<int>;
using vl=vector<ll>;
#define pb push_back
#define all(a) begin(a),end(a)

const int N=100010, M = 5000005,MOD=1e9+7;
const char en='\n';
const ll LLINF=1ll<<60;

int t, n, ok;
int len[N], sum[N];
string s[N];
int fq[M][26], tmp[26];

void calc (int i) {
	if (!ok) return;
	for (int k = 0; k < 26; k++) {
		fq[sum[i]][k] = 0;
	}
	for (int j = 0; j < len[i]; j++) {
		fq[sum[i]][s[i][j] - 'a']++;
	}
	//cout << "sad na " << i << endl;
	if (i == n) return;
	
	for (int j = 1; j <= len[i + 1]; j++) {
	    //cout << "j je " << j << endl;
		if (fq[sum[i] + j][0] == -1) continue;
		int q = j / len[i];
		for (int k = 0; k < 26; k++) {
			tmp[k] = fq[sum[i] + j][k] - q * fq[sum[i]][k];
			if (tmp[k] < 0) {
				ok = 0;
				return;
			}
		}
		int pos = j % len[i];
		if (pos == 0) continue;

		//cout << "postavi uvjet " << i << " " << pos << endl;
		for (int k = 0; k < 26; k++) {
			//cout << tmp[k] << " ";
			if (fq[sum[i - 1] + pos][k] != -1 && fq[sum[i - 1] + pos][k] != tmp[k]) {
				ok = 0;
				return;
			}
			fq[sum[i - 1] + pos][k] = tmp[k];
		}
		//cout << endl;
	}
}

string reconstruct_first () {
	if (!ok) return "";
	string res = "";
	int prosli = 0;
	for (int k = 0; k < 26; k++) {
		fq[0][k] = 0;
	}
	for (int j = 1; j <= len[1]; j++) {
		if (fq[j][0] == -1) continue;
		for (int k = 0; k < 26; k++) {
			tmp[k] = fq[j][k] - fq[prosli][k];
			if (tmp[k] < 0) {
				ok = 0;
				return "";
			}
			for (int c = 0; c < tmp[k]; c++) {
				res += (char)(k + 'a');
			}
		}
		prosli = j;
	}
	return res;
}

int main () {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cin >> t;
	while (t--) {
		ok = 1;
		cin >> n;
		for (int i = 1; i <= n; i++) {
			cin >> s[i];
			len[i] = s[i].size();
			sum[i] = sum[i - 1] + len[i];
		}
		for (int j = 0; j <= sum[n]; j++) {
			for (int k = 0; k < 26; k++) {
				fq[j][k] = -1;
			}
		}
		for (int i = n; i >= 1; i--) {
			calc(i);
		}
		s[1] = reconstruct_first();
		if (!ok) {
			cout << "NO\n";
		} else {
			cout << "YES\n";
			cout << s[1] << '\n';
			for (int i = 2; i <= n; i++) {
				for (int j = 0; j < len[i]; j++) {
					s[i][j] = s[i - 1][j % len[i - 1]];
				}
				cout << s[i] << '\n';
			}
		}
	}
	return 0;
}