#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
#include <limits.h>
int max(int a , int b)
{
    if(a > b)
        return a;
    else
        return b;
}
int min(int a , int b)
{
    if(a < b)
        return a;
    else
        return b;
}
struct point
    {
    int x;
    int y;
};
typedef struct point point;

int main() {

    int q;
    scanf("%d",&q);
    while(q--)
    {
        int n;
        scanf("%d",&n);
        point* a = (point*) malloc (n * sizeof(point));
        for(int i = 0;i < n;i++)
            scanf("%d %d",&a[i].x , &a[i].y);
        
        int slope1 = 100;
        int slope2 = 100;
        int x1  = 10001, x2 = 10001 , y1 = 10001 , y2 = 10001;
        int i;
        int min = INT_MAX,max = INT_MIN;
        for(i = 0;i < n;i++)
        {
              if(a[i].x < min)
                  min = a[i].x;
        }
        x1 = min;
        
        min = INT_MAX;
          for(i = 0;i < n;i++)
        {
              if(a[i].y < min)
                  min = a[i].y;
        }
        y1 = min;
        
        for(i = 0;i < n;i++)
        {
            if(a[i].x > max)
                max = a[i].x;
        }
        x2 = max;
        
        max = INT_MIN;
          for(i = 0;i < n;i++)
        {
            if(a[i].y > max)
                max = a[i].y;
        }
        y2 = max;
       
        for(i = 0;i < n;i++)
        {
            if(a[i].x > x1 && a[i].x < x2 && a[i].y > y1 && a[i].y < y2)
                break;
        }
        if(i != n)
            printf("NO\n");
        else
            printf("YES\n");
    }
    return 0;
}