#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,n;
    int arr[10][2];
    cin >> q;
    int i,j,x1=10001,x2=-10001,y1=10001,y2=-10001;
    for(i=0;i<q;i++)
        {
        cin >> n;
        for(j=0;j<n;j++)
            {
            cin >> arr[j][0] >> arr[j][1];
            if(arr[j][0]<x1)
                x1=arr[j][0];
            if(arr[j][0]>x2)
                x2=arr[j][0];
            if(arr[j][1]<y1)
                y1=arr[j][1];
            if(arr[j][1]>y2)
                y2=arr[j][1];
        }
        for(j=0;j<n;j++)
            {
            if(((arr[j][0]==x1 || arr[j][0]==x2) && (arr[j][1]>=y1 || arr[j][1]<=y2)) || ((arr[j][1]==y1 || arr[j][1]==y2) && (arr[j][0]>=x1 || arr[j][0]<=x2)))
                {continue;}
                break;
        }
        if(j!=n)
            cout << "NO\n";
        else
            cout << "YES\n";
    }
    return 0;
}