#include<bits/stdc++.h>
using namespace std;
set<int> x;
set<int> y;

int ar[10];
int br[10];

int main()
{
	int q;
	scanf("%d",&q);
	while(q--)
	{
		x.clear();
		y.clear();
		int n;
		scanf("%d",&n);
		int mnx=10001;
		int mx=-10001;
		int mny=10001;
		int my=-10001;
		
		for(int i=0;i<n;i++)
		{
			int a,b;
			scanf("%d %d",&a,&b);
			ar[i]=a;
			br[i]=b;
			mnx=min(mnx,a);
			mny=min(mny,b);
			mx=max(mx,a);
			my=max(my,b);
		}
		//printf("%d %d\n",mx,my);
		int fl=0;
		for(int i=0;i<n;i++)
		{
			if(ar[i]==mnx||ar[i]==mx)
			{
				if(br[i]<=my&&br[i]>=mny)
				{
					continue;
				}
				else
				{
					fl=1;
					break;
				}
			}
			else if(br[i]==mny||br[i]==my)
			{
				if(ar[i]<=mx&&ar[i]>=mnx)
				{
					continue;
				}
				else
				{
					fl=1;
					break;
				}	
			}
			else
			{
				fl=1;
			}
		}
		if(fl==1)
		{
			printf("NO\n");
		}
		else
		{
			printf("YES\n");
		}
	}
}