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

int main() {
	/* Enter your code here. Read input from STDIN. Print output to STDOUT */
	int q, n;
	int x[10], y[10];
	cin >> q;
	while (q--)
	{
		cin >> n;
		int min_x, min_y;
		int max_x, max_y;
		bool flag = true;

		min_x = min_y = 100000;
		max_x = max_y = -100000;

		for (int i = 0; i < n; i++)
		{
			cin >> x[i] >> y[i];
			if (x[i] > max_x)
				max_x = x[i];
			if (x[i] < min_x)
				min_x = x[i];
			if (y[i] > max_y)
				max_y = y[i];
			if (y[i] < min_y)
				min_y = y[i];
		}

		for (int i = 0; i < n; i++)
		{
			if (x[i] != max_x && x[i] != min_x && y[i] != max_y && y[i] != min_y)
			{
				flag = false;
				break;
			}
		}
		if (flag)
			cout << "YES" << endl;
		else
			cout << "NO" << endl;
	}
	return 0;
}