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


int main() {
    int n,q,i;
    int x[10],y[10];
    cin>>q;
    for(int i1=0;i1<q;i1++){
        cin>>n;
        int minx=10001,maxx=-10001,miny=10001,maxy=-10001;
        for(i=0;i<n;i++){
            cin>>x[i]>>y[i];
            if(minx>x[i])
                minx=x[i];
            if(maxx<x[i])
                maxx=x[i];
            if(miny>y[i])
                miny=y[i];
            if(maxy<y[i])
                maxy=y[i];
        }
        for(i=0;i<n;i++){
            if(minx!=x[i] && maxx!=x[i] && miny!=y[i] && maxy!=y[i]){
                cout<<"NO"<<endl;
                break;
            }
        }
        if(i==n)
            cout<<"YES"<<endl;
    }
        
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}