#include <bits/stdc++.h>
using namespace std;

#define endl '\n'
#define ff first
#define ss second
#define pb push_back
#define mp make_pair

typedef long long llong;
typedef pair<int, int> pii;

void process(){

	int n;
	cin >> n;

	list<pii> l;

	int min_y = 1e5, max_y = -1e5; 
	int min_x = 1e5, max_x = -1e5;	

	for (int i = 0; i < n; i++) {

		int x, y;
		cin >> x >> y;

		l.pb( mp(x, y) );

		min_y = min(min_y, y);
		max_y = max(max_y, y);

		min_x = min(min_x, x);
		max_x = max(max_x, x);

	}

	for (auto it = l.begin(); it != l.end();) {

		if (it -> ss == min_y || it -> ss == max_y ||
			it -> ff == min_x || it -> ff == max_x) {
			
			it = l.erase(it);

		} else it++;

	}
	
	cout << (l.empty() ? "YES\n" : "NO\n");

}


void solve() {

	int n;
	cin >> n;

	for (int i = 0; i < n; i++) process();
	
}

int main() {

	ios_base::sync_with_stdio(0);
	cin.tie(0);

	#ifdef LOCAL
		ifstream in("in");
		cin.rdbuf(in.rdbuf());
	#endif

	solve();

	return 0;

}