#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
  int T;
  cin >> T;
  for(int t = 0; t < T; ++t) {
    int n;
    cin >> n;
    int x[10];
    int y[10];
    int minx = 10001, miny = 10001, maxx = -10001, maxy = -10001;
    for(int i = 0; i < n; ++i) {
      cin >> x[i] >> y[i];
      minx = min(x[i], minx);
      maxx = max(x[i], maxx);
      miny = min(y[i], miny);
      maxy = max(y[i], maxy);
    }
    bool is_rect = true;
    for(int i = 0; i < n; ++i) {
      if(x[i] != minx && x[i] != maxx && y[i] != miny && y[i] != maxy){
        is_rect = false;
        break;
      }
    }
    cout << (is_rect ? "YES" : "NO") << endl;
  }
  return 0;
}