#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int q,n,x[10],y[10],sumx=0,sumy=0;
        scanf("%d",&q);
        
        for(int i=0;i<q;i++)
        {
            scanf("%d",&n);
            for(int j=0;j<n;j++)
                {
                    scanf("%d %d",&x[j],&y[j]);
                
            }
            for(int j=0;j<n-1;j++)
               { if(x[j]!=x[j+1])
                    sumx++;
                if(y[j]!=y[j+1])
                    sumy++;
               }
            if((sumx==2||sumx<2) && (sumy==2||sumy<2))
                printf("YES\n");
            else printf("NO\n");
        }    
    return 0;
}