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


#define MAX_LEN 100
int x[MAX_LEN], y[MAX_LEN];

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */  
    int q;
    cin >> q;

    while ( q-- ) {

        int min_x = 1e5, min_y = 1e5, max_x=-1e5, max_y=-1e5;
        int n;
        cin >> n;
        for ( int i = 0; i <n; ++i ) {
            cin >> x[i] >> y[i];
            if ( x[i] > max_x ) {
                max_x = x[i];
            }
            if ( x[i] < min_x ) {
                min_x = x[i];
            }
            if ( y[i] > max_y ) {
                max_y = y[i];
            }
            if ( y[i] < min_y ) {
                min_y = y[i];
            }
        }
        bool isOk = true;
        for ( int i = 0; i < n; ++i ) {
            if ( x[i] != min_x && x[i]!=max_x &&
                y[i] != min_y && y[i]!= max_y )
            {
                isOk = false;
                break;
            }
        }
        cout << (isOk ? "YES" : "NO" ) << endl;
    }
    return 0;
}