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

int a[10][2];

int main() {
    int q;
    cin >> q;
    while(q--) {
        int n;
        cin >> n;
        cin >> a[0][0] >> a[0][1];
        int xmax = a[0][0], xmin = a[0][0], ymax = a[0][1], ymin = a[0][1];
        for(int i = 1; i < n; ++i) {
            cin >> a[i][0] >> a[i][1];
            xmax = max(xmax, a[i][0]);
            xmin = min(xmin, a[i][0]);
            ymax = max(ymax, a[i][1]);
            ymin = min(ymin, a[i][1]);
        }
        bool rect = true;
        for(int i = 0; i < n; ++i) {
            if(a[i][0] != xmax && a[i][0] != xmin && a[i][1] != ymax && a[i][1] != ymin) {
                rect = false;
                break;
            }
        }
        cout << (rect ? "YES" : "NO") << endl;
    }
    return 0;
}