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


int main() {
    int n;
    cin>>n;
    int x[10],y[10];
    while(n--){
        int q;
        bool value =true;
        cin>>q;
        for(int i=0;i<q;i++){
            cin>>x[i];
            cin>>y[i];
        }
        int min1=x[0];
        int max1=x[0];
        for(int i=0;i<q;i++){
            if(x[i]<min1)
                min1=x[i];
            if(x[i]>max1)
                max1=x[i];   
        }
        int min2=y[0];
        int max2=y[0];
        for(int i=0;i<q;i++){
            if(y[i]<min2)
                min2=y[i];
            if(y[i]>max2)
                max2=y[i];   
        }
        for(int i=0;i<q;i++){
            if((x[i]==min1 && (y[i]>=min2 || y[i]<=max2) ) || (x[i]==max1 && (y[i]>=min2 || y[i]<=max2) )||(y[i]==min2 && (x[i]>=min1 || x[i]<=max1) ) || (y[i]==max2 && (x[i]>=min1 || x[i]<=max1) ))
            {    continue;  }
            else
            {   value = false; 
                break;}
            
            
        }
        if(value)
            cout<<"YES"<<endl;
        else
            cout<<"NO"<<endl;
           
    }
      
    return 0;
}