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


int n;
int x[20], y[20];

const int inf = (int)1e9 + 123;

int main() {
    int t;
    cin >> t;
    while(t--) {
        cin >> n;
        int x_mini = inf, y_mini = inf, x_maxi = -inf, y_maxi = -inf;
        for (int i = 0; i < n; i++) {
            cin >> x[i] >> y[i];
            x_mini = min(x_mini, x[i]);
            y_mini = min(y_mini, y[i]);
            
            x_maxi = max(x_maxi, x[i]);
            y_maxi = max(y_maxi, y[i]);
        }
        bool bad = 0;
        for (int i = 0; i < n; i++) {
            if (x[i] == x_mini || x[i] == x_maxi || y[i] == y_mini || y[i] == y_maxi)
               {
               
            }
            else
                bad = 1;
        }
        cout << (bad ? "NO\n" : "YES\n");
    }
    return 0;
}