#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 n;
    cin >> n;
    for(int i=0;i<n;i++){
        int j;
        cin >> j;
        int x[4]={0};
        int y[4]={0};
        int miny = 100000;
        int minx = 100000;
        int maxy = -100000;
        int maxx = -100000;
        for(int c=0;c<j;c++){
            cin >> x[c] >> y[c];
            if(y[c] < miny)miny = y[c];
            if(maxy < y[c])maxy = y[c];
            if(x[c] < minx)minx = x[c];
            if(maxx < x[c])maxx = x[c];
        }
        bool flag = true;
        for(int k=0;k<j;k++){
            if(x[k] == minx || x[k] == maxx){
                flag = true;
            }else if(y[k] == miny || y[k] == maxy){
                flag = true;
            }else{
                cout << "NO" << endl;
                flag = false;
                break;
            }
        }
        if(flag)cout << "YES" << endl;
    }
    return 0;
}