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

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