#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
struct rect{
    int x,y;
}a[11];

int main() {
    int test;
    cin>>test;
    while(test--){
        int n,i=0;
        cin>>n;
        int minx,miny,maxx,maxy;
        cin>>a[i].x>>a[i].y;
        minx=a[i].x;
        maxx=a[i].x;
        miny=a[i].y;
        maxy=a[i].y;
        i++;
        while(i<n){
            cin>>a[i].x>>a[i].y;
            minx=(minx<a[i].x)?minx:a[i].x;
            miny=(miny<a[i].y)?miny:a[i].y;
            maxx=(maxx>a[i].x)?maxx:a[i].x;
            maxy=(maxy>a[i].y)?maxy:a[i].y;
            i++;
        }
        //cout<<minx<<" "<<maxx<<"\n";
        //cout<<miny<<" "<<maxy<<"\n";
        i=0;
        while(i<n){
            //cout<<i<<"\t";
            if((a[i].x!=minx)&&(a[i].x!=maxx)&&(a[i].y!=miny)&&(a[i].y!=maxy))
                break;
            i++;
        }
       // cout<<i<<"\t"<<n;
        if(i==n)
            cout<<"YES\n";
        else
            cout<<"NO\n";
    }
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}