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

vector<long>x(10),y(10);

long px1, px2, py1, py2;


int same_plane(long x_plane, long y_plane, long xf_plane, long yf_plane, long x_point, long y_point){
    int plane=0;
    
    
    return 0;    
}

void success(){cout<<"YES"<<endl;}
void fail(){cout<<"NO"<<endl;}

int main() {
    int q;
    //Input
    int qt;cin>>qt;for (int qti=0;qti<qt;qti++){
        cin>>q;
        for (int qi=0;qi<q;qi++){cin>>x[qi]>>y[qi];}

    
    int plane=1;
    if (q<3){
        plane=1;
    }
    else {
        sort(x.rbegin(), x.rend());
        sort(y.rbegin(), y.rend());
        px1=x[0];
        int foundx1=1, foundx2=0;
        px2=x[1];
        if(px2!=px1){foundx2=1;}
        //cout<<" px1"<<px1<<" px2:"<<px2;
        for (int qi=2;qi<q;qi++){
            if (foundx2==0){
                if (x[qi]!=px2){
                    foundx2=1;
                    px2=x[qi];
                }
            }
            else {
                if (foundx2==1){
                    if (x[qi]!=px2){
                        plane=0;
                    }
                }
                
            }
        }
        
        py1=y[0];
        int foundy1=1, foundy2=0;
        py2=y[1];
        if(py2!=py1){foundy2=1;}
        
        for (int qi=2;qi<q;qi++){
            if (foundy2==0){
                if (y[qi]!=py2){
                    foundy2=1;
                    py2=y[qi];
                }
            }
            else {
                if (foundy2==1){
                    if (y[qi]!=py2){
                        plane=0;
                    }
                }
                
            }
        }
    }
    if (plane==0){fail();}else{success();}
    }
    return 0; 
}