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

#define LL long long
#define F first
#define S second
#define MP make_pair
#define PB push_back
#define SZ(a) (int)(a.size())
#define BS(vec,val) (int)(lower_bound(vec.begin(),vec.end(),val) - vec.begin())
#define bitcount __builtin_popcountll
#define LET(it,container) __typeof(container.begin()) it(container.begin())
#define ITER(it,container) for(__typeof(container.begin()) it=container.begin();it!=container.end();it++)

#define PREC cout << setprecision(10) << fixed;
#define FIO ios_base::sync_with_stdio(0); cin.tie(NULL);
#define DB(x) cerr << #x << ": " << x << " ";
//-std=c++11
//#define TRACE
#ifdef TRACE
#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1>
void __f(const char* name, Arg1&& arg1){
	cerr << name << " : " << arg1 << std::endl;
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args){
	const char* comma = strchr(names + 1, ',');cerr.write(names, comma - names) << " : " << arg1<<" | ";__f(comma+1, args...);
}
#else
#define trace(...)
#endif
//FILE *fin = freopen("in","r",stdin);
//FILE *fout = freopen("out","w",stdout);
#define endl "\n"

const double PI = acos(-1.0);
const int MOD = 1e9 + 7;
const int INF = 1e9 + 9;
const int MX = 1e5 + 5;

int main()
{
	int q;
	cin >> q;
	while(q--)
	{
		int n;
		int x[15],y[15];
		cin >> n;	
		for(int i=0;i<n;i++) cin >> x[i] >> y[i];

		int mix,mx;
		int miy,may;
		mix = miy = INF;
		mx = may = -INF;
		
		for(int i=0;i<n;i++)
		{
			mix = min(mix,x[i]);
			mx = max(mx,x[i]);
			miy = min(miy,y[i]);
			may = max(may,y[i]);
		}

		int flag = 0;
		for(int i=0;i<n;i++)
		{
			if(x[i] != mix and x[i] != mx and y[i] != miy and y[i] != may)
			{
				flag = 1;
			}
		}
		if(flag == 1)
		{
			cout << "NO" << endl;
		}
		else
			cout << "YES" << endl;
	}
	
	return 0;
}