/*******************************************   saluja123  *************************************************/
#include<bits/stdc++.h>
#define ll long long
#define mod 1000000007
using namespace std;
int x[100],y[100];

int main()
{
//	freopen("in.txt","r",stdin);
//	freopen("out.txt","w",stdout);
	int q;
	cin>>q;
	while(q--)
	{
		int n;
		cin>>n;
	
		int minx,miny,maxx,maxy;
		maxy=maxx=-1000000;
		miny=minx=1000000;
		for(int i=0;i<n;i++)
		{
			cin>>x[i]>>y[i];
			minx=min(minx,x[i]);
			miny=min(miny,y[i]);
			maxx=max(maxx,x[i]);
			maxy=max(maxy,y[i]);
		}
		
		bool flag=1;
		for(int i=0;i<n;i++)
		{
			if(x[i]!=minx&&x[i]!=maxx&&y[i]!=miny&&y[i]!=maxy)
			{
				flag=0;
				break;
			}
		}
		if(flag)
		cout<<"YES"<<endl;
		else
            cout<<"NO"<<endl;
	/*	{
			maxy=maxx=-1000000;
			miny=minx=1000000;
			for(int i=0;i<n;i++)
			{
				minx=min(minx,x[i]+y[i]);
				miny=min(miny,x[i]-y[i]);
				maxx=max(maxx,x[i]+y[i]);
				maxy=max(maxy,x[i]-y[i]);
			}
			
			flag=1;
			for(int i=0;i<n;i++){
				if((x[i]+y[i])!=minx&&(x[i]+y[i])!=maxx&&(x[i]-y[i])!=miny&&(x[i]-y[i])!=maxy)
				{
					flag=0;
					break;
				}
			}
			
			if(flag)
			cout<<"YES"<<endl;
			else
			cout<<"NO"<<endl;
		}*/
		
	}
	return 0;
}