#include <cstring>
#include <iostream>
#include <map>
#include <string>
#include <vector>
#define endl '\n'
#define rep(i, x, y) for (int i = x; i <= y; i++)
using namespace std;
const int N = 1e5 + 5, M = 5e6 + 5;
struct node {
    int len;
    int c[26];
} a[N], re[N];
map<int, node> f;
char ans[M];

void solve() {
    bool flag = 1;
    int n;
    f.clear();
    memset(a, 0, sizeof(a));

    cin >> n;
    rep(i, 1, n) {
        string s;
        cin >> s;
        int len = s.size();
        a[i].len = len;
        rep(j, 0, len - 1) a[i].c[s[j] - 'a']++;
    }
    int last = 0;

    auto check = [&](node A, node B) {
        rep(i, 0, 25) if (A.c[i] < B.c[i]) {
            flag = 0;
            return;
        }
        return;
    };

    for (int i = n; i >= 1; i--) {
        if (a[i].len > last) f[a[i].len] = a[i];
        else {
            int cnt = 0;
            for (auto it = --f.end();; it = --f.end()) {
                if (it->second.len <= a[i].len) break;
                node now;
                now.len = it->second.len % a[i].len;
                int x = it->second.len / a[i].len;
                rep(j, 0, 25) {
                    now.c[j] = it->second.c[j] - a[i].c[j] * x;
                    if (now.c[j] < 0) flag = 0;
                }
                if (!flag) break;
                re[++cnt] = now;
                if (it == f.begin()) {
                    f.erase(it);
                    break;
                } else f.erase(it);
            }
            if (!flag) break;
            re[++cnt] = a[i];
            rep(i, 1, cnt) if (f.find(re[i].len) == f.end()) f[re[i].len] = re[i];
            else check(f[re[i].len], re[i]); }
        last = a[i].len;
    }
    node now;
    now.len = 0;
    rep(i, 0, 25) now.c[i] = 0;
    int k = 0;

    for (auto it = f.begin(); it != f.end(); it++) {
        check(it->second, now);
        if (!flag) break;
        rep(j, 0, 25) rep(s, now.c[j] + 1, it->second.c[j]) ans[++k] = j + 'a';
        now = it->second;
    }

    if (!flag) {
        cout << "NO" << endl;
        return;
    }
    cout << "YES" << endl;

    {
        rep(i, 1, k) cout << ans[i];
        cout << endl;
        rep(i, 2, n) {
            int len = k;
            rep(j, len + 1, a[i].len) ans[j] = ans[(j - 1) % len + 1];
            rep(j, 1, a[i].len) cout << ans[j];
            cout << endl;
            k = a[i].len;
        }
    }
}

int main() {
    // ios::sync_with_stdio(0); cin.tie(0);
    int T;
    cin >> T;
    while (T--) solve();
    return 0;
}