#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 t;
    cin>>t;
    while(t--)
    {
        int n,mix=10001,max=-10001,miy=10001,may=-10001;
        cin>>n;
        int x[n],y[n];
        for(int i=0;i<n;i++)
        {
            cin>>x[i]>>y[i];
            if(mix>x[i])
            {
                mix=x[i];
            }
            if(miy>y[i])
            {
                miy=y[i];
            }    
            if(max<x[i])
            {
                max=x[i];
            }    
            if(may<y[i])
            {
                may=y[i];
            }    
        }   
        int k=0;
       // cout<<mix<<" "<<max<<" "<<miy<<" "<<may<<endl;
        for(int i=0;i<n && k==0;i++)
        {
            if(!(mix==x[i] || max==x[i] ))
            {
                if(!( miy==y[i] || may==y[i] ))
                {
                    k++;
                }    
            }
              
        }    
        if(k==0)
        {
            cout<<"YES"<<endl;
        }    
        else
        {
            cout<<"NO"<<endl;
        }    
    }    
    return 0;
}