#include<bits/stdc++.h>
using namespace std;

#define F first
#define S second
#define pb push_back
#define mp make_pair
#define var(X) cerr << " --> " << #X << " = " << X << endl
#define arr(a,n) for(int i=0;i<n;i++){if(i==0) cout<<"Results for array "<< #a <<"\n";cout<<a[i]<<" ";} cout<<endl
#define arr1(a,n) for(int i=1;i<=n;i++){if(i==1) cout<<"Results for array "<< #a <<"\n";cout<<a[i]<<" ";} cout<<endl

//setbase - cout << setbase (16); cout << 100 << endl; Prints 64
//setfill -   cout << setfill ('x') << setw (5); cout << 77 << endl; prints xxx77
//setprecision - cout << setprecision (4) << f << endl; Prints x.xxxx

typedef long long ll;
typedef vector<int> vi;
typedef pair<int,int> ii;
typedef vector<pair<int,int> > vii;
const double eps = 1e-10, pi = acos(-1.0);

int a[15],b[15];

int main()
{
	/*
	#ifndef ONLINE_JUDGE
	freopen("input.txt","r",stdin);
	freopen("out.txt","w",stdout);
	#endif
	*/
	
	int t=1,cs=1;
	//ios_base::sync_with_stdio(0); cin.tie(0);	
	//clock_t start=clock();
	scanf("%d",&t);
	while(t--)
	{
		int n,f=1,xmax=-10000,ymax=-10000,xmin=10000,ymin=10000;
		cin>>n;
		for(int i=0;i<n;i++)
		{
			cin>>a[i]>>b[i];
			xmax=max(a[i],xmax);
			xmin=min(a[i],xmin);
			ymax=max(b[i],ymax);
			ymin=min(b[i],ymin);
		}
		//cout<<xmax<<' '<<xmin<<endl;
		
	//	cout<<ymax<<' '<<ymin<<endl;
		for(int i=0;i<n;i++)
		if(a[i]!=xmax && a[i]!=xmin && b[i]!=ymax && b[i]!=ymin)
		{
			f=0;
			break;
		}
		else if(a[i]==xmax || a[i]==xmin)
		{
			if(b[i]<ymin || b[i]>ymax)
			{
				f=0;
				break;
			}
		}
		else 
		{
			if(a[i]<xmin || a[i]>xmax)
			{
				f=0;
				break;
			}
		}
		if(f==0)
		cout<<"NO\n";
		else
		cout<<"YES\n";
	}
	//clock_t end=clock();
	//cout <<"Time: " <<(double)(end-start)/CLOCKS_PER_SEC <<" seconds" <<endl;
	return 0;
}