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

bool b;
int Q, mxx,mnx,mxy,mny,x[10],y[10],n;
int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    cin>>Q;
    for(int q=0; q<Q; q++) {
        cin>>n;
        mnx = mny = 1e6;
        mxx = mxy = -mnx;
        b = false;
        for(int i=0; i<n; i++)
            cin>>x[i]>>y[i],
            mxx = max(mxx, x[i]),
            mnx = min(mnx, x[i]),
            mxy = max(mxy, y[i]),
            mny = min(mny, y[i]);
        for(int i=0; i<n; i++)
            if(x[i]!=mxx && x[i]!=mnx && y[i]!=mxy && y[i]!=mny) b = true;
        if(b) cout<<"NO\n"; else cout<<"YES\n";
    }
    return 0;
}