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


int main() {
    int q, n, i, xmin, xmax, ymin, ymax, ans;
    int x[10], y[10];
    cin>>q;
    while(q--)
    {
        cin>>n;
        cin>>x[0]>>y[0];
        xmin = xmax = x[0];
        ymin = ymax = y[0];
        for(i=1; i<n; i++)
        {
            cin>>x[i]>>y[i];
            if (x[i] < xmin)
                xmin = x[i];
            if (x[i] > xmax)
                xmax = x[i];
            if (y[i] < ymin)
                ymin = y[i];
            if (y[i] > ymax)
                ymax = y[i];
        }
        ans = 1;
        for(i=0; i<n; i++)
        {
            if (x[i] > xmin && x[i] < xmax && y[i] > ymin && y[i] < ymax)
            {
                ans = 0;
                break;
            }
        }
        if (ans)
            cout<<"YES\n";
        else
            cout<<"NO\n";
    }
    return 0;
}