#include<iostream>
#include<stdio.h>
using namespace std;
int main()
{
    int test,n,x[10],y[10];
    scanf("%d",&test);
    while(test--)
    {
        int xx1=-100000,yy1=-100000,xx2=100000,yy2=100000;
        scanf("%d",&n);
        int i;
        int flag=0;
        for(i=0;i<n;i++)
        {
            scanf("%d%d",&x[i],&y[i]);
            if(x[i]>xx1)
                xx1=x[i];
            if(y[i]>yy1)
                yy1=y[i];
            if(x[i]<xx2)
                xx2=x[i];
            if(y[i]<yy2)
                yy2=y[i];
        }
        //printf("\n\n%d %d",yy1,yy2);
        for(i=0;i<n;i++)
        {
            if(x[i]!=xx1 && x[i]!=xx2 && y[i]!=yy1 && y[i]!=yy2)
                flag=1;
        }
        if(flag==0)
            printf("YES\n");
        else
            printf("NO\n");

    }
    return 0;
}