#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <bits/stdc++.h>
using namespace std;


int main() {
    int t; cin>>t;
    while(t--){
        int n; cin>>n;
        int x[n],y[n];
        int x1=INT_MAX,x2=INT_MIN,y1=INT_MAX,y2=INT_MIN;
        for(int i=0;i<n;i++){
            cin>>x[i]>>y[i];   
            x1=min(x1,x[i]);
            x2=max(x2,x[i]);
            y1=min(y1,y[i]);
            y2=max(y2,y[i]);
        } 
        //cout<<x1<<" "<<x2<<" "<<y1<<" "<<y2<<endl;
        //int a=x[1]-x[0],b=y[1]-y[0];
        bool flag=0;
        for(int i=0;i<n;i++){
            //int x=
            if(x[i]!=x1&&x[i]!=x2&&y[i]!=y1&&y[i]!=y2){
                flag=1;
                break;
            }
        }
        if(flag) cout<<"NO"<<endl;
        else cout<<"YES"<<endl;
    }
    return 0;
}