#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>

int main() {
    int q,i;
    scanf("%d",&q);
    while(q--){
        long int n,x[10],y[10],maxx=-10000,maxy=-10000,minx=10000,miny=10000,flag=0;
        scanf("%ld",&n);
        for(i=0;i<n;i++){
            scanf("%ld%ld",&x[i],&y[i]);
            if(x[i]<minx)
                minx=x[i];
             if(y[i]<miny)
                miny=y[i];
             if(x[i]>maxx)
                maxx=x[i];
             if(y[i]>maxy)
                maxy=y[i];
        }
        for(i=0;i<n;i++){
            if((x[i]!=maxx)&&(x[i]!=minx)&&(y[i]!=maxy)&&(y[i]!=miny)){
               flag=1;
                break;
            }
        }
        if(flag==0)
        printf("YES\n");
        else
            printf("NO\n");
    }
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */    
    return 0;
}