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


int main() {
    int q,n,v,r;
    int i,j;
    cin>>q;
    while(q--)
        {
        cin>>n;
        int x[15],y[15];
        for(i=0;i<n;i++)
            cin>>x[i]>>y[i];
        int minx=x[0],miny=y[0],maxx=x[0],maxy=y[0];
        for(i=1;i<n;i++)
            {
            if(x[i]<=minx)
                minx = x[i];
            if(x[i]>=maxx)
                maxx = x[i];
            if(y[i]<=miny)
                miny = y[i];
            if(y[i]>=maxy)
                maxy = y[i];
        }
        int flag=0;
        for(i=0;i<n;i++)
        {
            if(x[i]==minx && y[i]<=maxy && y[i]>=miny)
                flag=0;
            else if(x[i]==maxx && y[i]<=maxy && y[i]>=miny)
                flag = 0;
                else if(y[i]==miny && x[i]<=maxx && x[i]>=minx)
                flag = 0;
                else if(y[i]==maxy && x[i]<=maxx && x[i]>=minx)
                    flag = 0;
                else
                {
                flag = 1;
                break;
            }

                
            
        }
        if(!flag)
                cout<<"YES\n";
            else
                cout<<"NO\n";
    }
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}