#if __INCLUDE_LEVEL__ == 0

#include __BASE_FILE__

namespace {

using A = std::array<int, 26>;

void solve() {
  int n;
  scan(n);
  std::vector<std::string> s(n);
  scan(s);

  const auto op = [&](const A& x, const A& y) -> A {
    A z;
    for (const int i : rep(len(z))) {
      z[i] = x[i] + y[i];
    }
    return z;
  };
  const auto e = A{};
  const auto inv = [&](A x) -> A {
    for (int& e : x) {
      e = -e;
    }
    return x;
  };

  std::vector<A> count(n);
  for (const int i : rep(n)) {
    for (const char c : s[i]) {
      ++count[i][c - 'a'];
    }
  }

  std::vector<weighted_dsu<A, decltype(op), decltype(inv)>> dsu;
  for (const int i : rep(n)) {
    dsu.emplace_back(len(s[i]) + 1, op, e, inv);
    dsu[i].unite(0, len(s[i]), count[i]);
  }

  for (const int i : rep(n - 1) | views::reverse) {
    std::vector<int> p;
    for (const int j : rep(len(s[i + 1]) + 1)) {
      if (dsu[i + 1].same(0, j)) {
        p.push_back(j);
      }
    }

    for (const int k : rep(len(p) - 1)) {
      int l = p[k];
      int r = p[k + 1];
      A w = dsu[i + 1].diff(l, r);
      const int ql = l / len(s[i]);
      const int qr = r / len(s[i]);
      for (const int t : rep(26)) {
        w[t] += count[i][t] * ql;
        w[t] -= count[i][t] * qr;
      }
      const int rl = l - ql * len(s[i]);
      const int rr = r - qr * len(s[i]);
      if (dsu[i].same(rl, rr)) {
        if (dsu[i].diff(rl, rr) != w) {
          print("NO");
          return;
        }
      } else {
        dsu[i].unite(rl, rr, w);
      }
    }
  }

  for (const int i : rep(n - 1)) {
    std::vector<int> p;
    for (const int j : rep(len(s[i]) + 1)) {
      if (dsu[i].same(0, j)) {
        p.push_back(j);
      }
    }

    for (const int k : rep(len(p) - 1)) {
      const A w = dsu[i].diff(p[k], p[k + 1]);
      for (int l = p[k], r = p[k + 1]; r <= len(s[i + 1]); l += len(s[i]), r += len(s[i])) {
        if (dsu[i + 1].same(l, r)) {
          if (dsu[i + 1].diff(l, r) != w) {
            print("NO");
            return;
          }
        } else {
          dsu[i + 1].unite(l, r, w);
        }
      }
    }
  }

  for (const int i : rep(n)) {
    std::vector<int> p;
    for (const int j : rep(len(s[i]) + 1)) {
      if (dsu[i].same(0, j)) {
        p.push_back(j);
      }
    }

    for (const int k : rep(len(p) - 1)) {
      int l = p[k];
      int r = p[k + 1];
      A w = dsu[i].diff(l, r);
      if (ranges::min(w) < 0) {
        print("NO");
        return;
      }
      int cur = 0;
      for (const int j : rep(l, r)) {
        while (w[cur] == 0) {
          ++cur;
        }
        s[i][j] = static_cast<char>('a' + cur);
        --w[cur];
      }
    }
  }

  print("YES");
  for (const int i : rep(n)) {
    print(s[i]);
  }
}

}  // namespace

int main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(nullptr);

  int t;
  scan(t);
  while (t--) {
    solve();
  }
}

#else  // __INCLUDE_LEVEL__

#include <bits/stdc++.h>

template <class T, class Op, class Inv>
struct weighted_dsu {
  Op op;
  T e;
  Inv inv;
  std::vector<int> p, sz;
  std::vector<T> d;
  weighted_dsu(int n, Op _op, T _e, Inv _inv)
      : op(_op), e(_e), inv(_inv), p(n, -1), sz(n, 1), d(n, e) {}
  int root(int v) {
    if (p[v] == -1) {
      return v;
    }
    if (p[p[v]] == -1) {
      return p[v];
    }
    int ov = v;
    T a = e;
    while (p[v] != -1) {
      for (int i = 0; i < 26; i++) {
        a[i] += d[v][i];
      }
      v = p[v];
    }
    d[ov] = a;
    p[ov] = v;
    return v;
  }
  void unite(int u, int v, T w) {
    int ou = u, ov = v;
    u = root(u);
    v = root(v);
    assert(u != v);
    if (sz[u] < sz[v]) std::swap(u, v), std::swap(ou, ov), w = inv(w);
    p[v] = u;
    sz[u] += sz[v];
    for (int i = 0; i < 26; i++) {
      d[v][i] = d[ou][i] + w[i] - d[ov][i];
    }
  }
  T diff(int u, int v) {
    int ou = u, ov = v;
    u = root(u), v = root(v);
    T dv = d[ov];
    assert(u == v);
    for (int i = 0; i < 26; ++i) {
      dv[i] -= d[ou][i];
    }
    return dv;
  }
  bool same(int u, int v) { return root(u) == root(v); }
  int size(int v) { return sz[root(v)]; }
};
template <class T, class Op, class Inv>
auto make_weighted_dsu(int n, Op op, T e, Inv inv) {
  return weighted_dsu<T, Op, Inv>(n, op, e, inv);
}

template <class T, class U = T>
bool chmin(T& x, U&& y) {
  return y < x && (x = std::forward<U>(y), true);
}

template <class T, class U = T>
bool chmax(T& x, U&& y) {
  return x < y && (x = std::forward<U>(y), true);
}

template <std::signed_integral T = int>
T inf() {
  T ret;
  std::memset(&ret, 0x3f, sizeof(ret));
  return ret;
}

template <std::floating_point T>
T inf() {
  return std::numeric_limits<T>::infinity();
}

template <class T>
concept Range = std::ranges::range<T> && !std::convertible_to<T, std::string_view>;

template <class T>
concept Tuple = std::__is_tuple_like<T>::value && !Range<T>;

namespace std {

istream& operator>>(istream& is, Range auto&& r) {
  for (auto&& e : r) {
    is >> e;
  }
  return is;
}

istream& operator>>(istream& is, Tuple auto&& t) {
  return apply([&](auto&... xs) -> istream& { return (is >> ... >> xs); }, t);
}

ostream& operator<<(ostream& os, Range auto&& r) {
  for (string_view sep = ""; auto&& e : r) {
    os << exchange(sep, " ") << e;
  }
  return os;
}

ostream& operator<<(ostream& os, Tuple auto&& t) {
  const auto f = [&](auto&... xs) -> ostream& {
    [[maybe_unused]] string_view sep = "";
    ((os << exchange(sep, " ") << xs), ...);
    return os;
  };
  return apply(f, t);
}

}  // namespace std

#define DEF_INC_OR_DEC(op) \
  auto& operator op(Range auto&& r) { \
    for (auto&& e : r) { \
      op e; \
    } \
    return r; \
  } \
  auto& operator op(Tuple auto&& t) { \
    std::apply([](auto&... xs) { (op xs, ...); }, t); \
    return t; \
  }

DEF_INC_OR_DEC(++)
DEF_INC_OR_DEC(--)

#undef DEF_INC_OR_DEC

void scan(auto&&... xs) { std::cin >> std::tie(xs...); }
void print(auto&&... xs) { std::cout << std::tie(xs...) << '\n'; }

template <class F>
class fix {
 public:
  explicit fix(F f) : f_(std::move(f)) {}

  decltype(auto) operator()(auto&&... xs) const {
    return f_(std::ref(*this), std::forward<decltype(xs)>(xs)...);
  }

 private:
  F f_;
};

inline auto rep(int l, int r) { return std::views::iota(std::min(l, r), r); }
inline auto rep(int n) { return rep(0, n); }
inline auto rep1(int l, int r) { return rep(l, r + 1); }
inline auto rep1(int n) { return rep(1, n + 1); }

namespace ranges = std::ranges;
namespace views = std::views;

using i64 = std::int64_t;

#define len(...) static_cast<int>(ranges::size(__VA_ARGS__))

#endif  // __INCLUDE_LEVEL__