#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>

#define INF 100000
using namespace std;
struct point{int x, y;};
int q, n, Xmin, Xmax, Ymax, Ymin;
point p[11];
int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    cin >> q;
    while(q--)
    {
        cin >> n;
        Xmax = Ymax = - INF;
        Xmin = Ymin = INF;
        for(int i = 1; i <= n; i ++)
        {
            cin >> p[i].x >> p[i].y;
            if(p[i].x < Xmin)
                Xmin = p[i].x;
            if(p[i].x > Xmax)
                Xmax = p[i].x;
            if(p[i].y < Ymin)
                Ymin = p[i].y;
            if(p[i].y > Ymax)
                Ymax = p[i].y;
        }
        
        int i;
        for(i = 1; i <= n; i++)
        {
            if( (p[i].x == Xmin || p[i].x == Xmax) && (p[i].y <= Ymax && p[i].y >= Ymin) )
                continue;
            if( (p[i].y == Ymin || p[i].y == Ymax) && (p[i].x <= Xmax && p[i].x >= Xmin) )
                continue;
            break;
        }
        
        cout << ( (i > n) ? "YES": "NO" ) << '\n';
    }
    return 0;
}