#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 q,n;
    scanf("%d",&q);
    while(q--)
        {
        scanf("%d",&n);
        int i,x[n],y[n];
        for(i=0;i<n;i++)
            scanf("%d %d",&x[i],&y[i]);
        if(n==1||n==2)
            printf("YES\n");
        else if(n==3)
            {
            if((x[0]=x[1]&&y[1]==y[2]&&x[2]=x[0])||(x[1]=x[2]&&y[2]==y[0]&&x[0]=x[1])(x[2]=x[0]&&y[0]==y[1]&&x[1]=x[2]) || (x[0]=x[1]&&y[1]==y[2]&&y[2]=y[0])||(x[1]=x[2]&&y[2]==y[0]&&y[0]=y[1])(x[2]=x[0]&&y[0]==y[1]&&y[1]=y[2]))
        }
        else if(n==4)
            {
            if((x[0]=x[1]&&y[1]==y[2]&&x[2]=x[3]&&y[3]==y[0])||(x[1]=x[2]&&y[2]==y[3]&&x[3]=x[0]&&y[0]==y[1])||(x[2]=x[3]&&y[3]==y[0]&&x[0]=x[1]&&y[1]==y[2])||(x[3]=x[0]&&y[0]==y[1]&&x[1]=x[2]&&y[2]==y[3]))
                printf("YES\n");
            else printf("NO\n");
        }
        else
            printf("NO\n");
    }
    return 0;
}