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

typedef long long LL;
LL cross(pair < LL , LL > A , pair < LL , LL > B){
    return A.first * B.second - A.second * B.first;
}
pair < LL , LL > dif(pair < LL , LL > A, pair < LL , LL > B)
{
    return {B.first-A.first , B.second - A.second};
}

pair < LL , LL > gg;
bool cmp(pair < LL , LL > &A , pair < LL , LL > &B)
{
    return cross(dif(gg,A) , dif(gg,B))>0;
}
int main() {
    int Q  , N , i ;
    cin>>Q;
    for(;Q;--Q){
        cin>>N;
        vector < pair < LL , LL > > A(N);
        vector < LL > X(N) , Y(N);
        for(i=0;i<N;++i)
        {
            cin>>A[i].first>>A[i].second;
            X[i] = A[i].first;
            Y[i] = A[i].second;
        }
        sort(X.begin(),X.end());
        sort(Y.begin(),Y.end());
        int x_min = X[0] , x_max = *X.rbegin() ;
        int y_min = Y[0] , y_max = *Y.rbegin() ;
        bool flag = 1;

        for(i=0;i<N;++i)
        {
            if(A[i].first!=x_min && A[i].first!=x_max && A[i].second!=y_max && A[i].second!=y_min )
                flag = 0 ;

        }
        puts(flag?"YES":"NO");
    }
    return 0;
}