#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 q;
    cin>>q;
    while(q--){
        int n,x1[12],y1[12];
        int flag=0;
        cin>>n;
        int minx=100000;
        int miny=100000;
        int maxx=-100000;
        int maxy=-100000;
        //cout<<"yo";
        for(int i=0;i<n;i++){
            cin>>x1[i]>>y1[i];
            if(x1[i]>maxx)
                maxx=x1[i];
            if(x1[i]<minx)
                minx=x1[i];
            if(y1[i]>maxy)
                maxy=y1[i];
            if(y1[i]<miny)
                miny=y1[i];
        }
        //cout<<minx<<" "<<maxx<<" "<<miny<<" "<<maxy;
        for(int i=0;i<n;i++){
            if(x1[i]!=maxx&&x1[i]!=minx)
                {
                flag=1;
            }
            if(y1[i]!=maxy&&y1[i]!=miny)
                {
                flag=1;
            }
        }
        if(flag==0)
            cout<<"YES"<<endl;
        else
            cout<<"NO"<<endl;
    }
    return 0;
}