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

struct point {
    unsigned long int x;
    unsigned long int y;
};

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) {
        struct point p[10];
        int minX, maxX, minY, maxY, t;
        
        cin >> t;
        for (int j = 0; j < t; ++j) {
            cin >> p[j].x;
            cin >> p[j].y;
        }
        
        minX = p[0].x;
        maxX = p[0].x;
        for (int j = 1; j < t; ++j) {
            if (minX > p[j].x) minX = p[j].x;
            if (maxX < p[j].x) maxX = p[j].x;
        }
        minY = p[0].y;
        maxY = p[0].y;
        
        for (int j = 1; j < t; ++j) {
            if (minY > p[j].y) minY = p[j].y;
            if (maxY < p[j].y) maxY = p[j].y;
        
        }
        
        for (int j = 0; j < t; ++j) {
            bool a = (minX < p[j].x) && (p[j].x < maxX);
            bool b = (minY < p[j].y) && (p[j].y < maxY);
            
            if (a && b) {
                cout << "NO" << endl;
                exit(0);
            }
                        
        }
        cout << "YES" << endl;
                
    }
    
    return 0;
}