#include<bits/stdc++.h>
using namespace std;
#define mod 1000000007
#define pb push_back
#define mp make_pair
#define Int long long
#define fs first
#define sc second
#define gcd __gcd
#define inf 1e15
int main(){
	
	/*string s;
	cin>>s;
	int n = s.size();
	if(s[n-1]=='E'){
		cout<<n-1<<endl;
		return 0;
	}
	if(s[0] == 'E'){
		cout<<0<<endl;
		return 0;
	}
	int i,a=-1,b=-1;
	for(i=n-3;i>0;i--){
		if(s[i]=='E' && s[i+1]=='E' && s[i+2]=='O'){
			a = i;
			break;
		}
	}
	for(i=n-2;i>1;i--){
		if(s[i]=='E' && s[i-1]=='E' && s[i-2]=='O'){
			b = i;
			break;
		}
	}
	if(a==-1 && b==-1){
		for(i=n-2;i>1;i--){
			if(s[i]=='E' && s[i+1]=='E'){
				a = i;
				break;
			}
		}
		for(i=n-2;i>1;i--){
			if(s[i]=='E' && s[i-1]=='E'){
				a = i;
				break;
			}
		}
		if(a==-1 && b==-1){
			for(i=n-2;i>1;i--){
				if(s[i]=='E'){
					a = i;
					break;
				}
			}
			cout<<a<<endl;
		}else{
			cout<<max(a,b)<<endl;
		}
	}else{
		cout<<max(a,b)<<endl;
	}*/
	Int m,n,i,x[10004],y[10004],xmax,xmin,ymax,ymin;
	cin>>m;
	while(m--){
		cin>>n;
		xmax = ymax = LLONG_MIN;
		ymin = xmin = LLONG_MAX;
		for(i=1;i<=n;i++){
			cin>>x[i]>>y[i];
			if(xmax<x[i])
				xmax=x[i];
			if(xmin>x[i])
				xmin=x[i];
			if(ymax<y[i])
				ymax=y[i];
			if(ymin>y[i])
				ymin=y[i];
		}
		for(i=1;i<=n;i++){
			if(x[i]!=xmin && x[i]!=xmax && y[i]!=ymax && y[i]!=ymin){
				cout<<"NO\n";
				break;
			}
		}
		if(i>n)
			cout<<"YES\n";
	}
	return 0;
}