#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;
    for (int i = 0; i < q; i++){
        int n;
        cin >> n;
        
        int xs[n];
        int ys[n];
        int bigX = -100000, bigY = -100000;
        int smaX = 100000, smaY = 100000;
        
        for (int j = 0; j < n; j++){
            int x, y;
            cin >> x >> y;
            xs[j] = x;
            ys[j] = y;
    
            if (x > bigX){
                bigX = x;
            }
            if (x < smaX){
                smaX = x;
            }
            if (y < smaY){
                smaY = y;
            }
            if (y > bigY){
                bigY = y;
            }
        }
        
        bool dege = true;
        
        for (int j = 0; j < n; j++){
            bool x_side = (xs[j] == 0) || (xs[j] == bigX) || (xs[j] == smaX);
            bool y_side = (ys[j] == 0) || (ys[j] == bigY) || (ys[j] == smaY);
            
            if ( !x_side && !y_side ){
                dege = false;
                break;
            }
        }
        
        if (dege){
            cout << "YES" << endl;
        }else{
            cout << "NO" << endl;
        }
    }
    
    return 0;
}