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

#define FOR(i, a, b) for (int i=(a); i < (b); i++)
#define RFOR(i, b, a) for (int i = (b)-1; i >= (a); i--)
#define ITER(it, a) for (__typeof(a.begin()) it = a.begin(); it != a.end(); it++)
#define FILL(a, value) memset(a, value, sizeof(a))

#define SZ(a) (int)a.size()
#define ALL(a) a.begin(), a.end()
#define MP make_pair
#define PB push_back

typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PII;

const double PI = acos(-1.0);
const int INF = 1000 * 1000 * 1000 + 7;
const LL LINF = INF * (LL) INF;

const int MAX = 200005;


struct Point
{
	int x,y;
	Point operator - (Point b)
	{
		Point res;
		res.x=x-b.x;
		res.y=y-b.y;

		return res;
	}

	LL vm(Point b)
	{
		return x*b.y-y*b.x;
	}

	bool cw(Point b)
	{
		return vm(b)>=0;
	}

	bool ccw(Point b)
	{
		return vm(b)<=0;
	}

	LL sc(Point b)
	{
		return x*b.x+y*b.y;
	}

};

Point p[47];
int main()
{
	//freopen("in.txt", "r", stdin);
	//ios::sync_with_stdio(false); cin.tie(0);

	int q;
	cin>>q;
	FOR(qq,0,q)
	{
		int n;
		cin>>n;

		FOR(i,0,n)
		{
			cin>>p[i].x>>p[i].y;
		}


		

		int lx =INF,rx=-INF,ly=INF,ry=-INF;

		FOR(i,0,n)
		{
			lx = min(lx,p[i].x);
			rx = max(rx,p[i].x);
			ly = min(ly,p[i].y);
			ry = max(ry,p[i].y);
		}
		bool ok = true;
		//if(lx==rx || ly==ry)ok=false;
		FOR(i,0,n)
		{
			if((lx == p[i].x || rx == p[i].x) &&(ly<=p[i].y && ry>=p[i].y) )continue;
			if((ly == p[i].y || ry == p[i].y) &&(lx<=p[i].x && rx>=p[i].x) )continue;
			ok=false;
		}

		if(ok)
		{
			cout<<"YES\n";
		}
		else cout<<"NO\n";
	}
}