#include <cstdio>
#include <set>

using namespace std;

const int kMaxN = 16;

int N;
int x[kMaxN], y[kMaxN];

bool solve() {
  scanf("%d", &N);
  for (int i = 0; i < N; i++)
    scanf("%d %d", &x[i], &y[i]);

  if (set<int>(x, x+N).size() == 1) return true;
  if (set<int>(y, y+N).size() == 1) return true;

  for (int L = 0; L < N; L++)
    for (int R = 0; R < N; R++)
      for (int T = 0; T < N; T++)
        for (int B = 0; B < N; B++) {
          bool ok = true;
          for (int i = 0; ok && i < N; i++) {
            ok &=
              (x[i] == x[L] && y[i] <= y[T] && y[i] >= y[B]) ||
              (x[i] == x[R] && y[i] <= y[T] && y[i] >= y[B]) ||
              (y[i] == y[B] && x[i] <= x[R] && x[i] >= x[L]) ||
              (y[i] == y[T] && x[i] <= x[R] && x[i] >= x[L]);
          }
          if (ok) return true;
        }

  return false;
}

int main() {
#ifdef LocalHost
  freopen("input.txt", "rt", stdin);
#endif

  int T;
  scanf("%d", &T);
  for (int i = 0; i < T; i++)
    printf(solve() ? "YES\n" : "NO\n");

  return 0;
}