#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#define inf 1000000000
using namespace std;

int n;

int x[20], y[20];

inline void solve()
{
    int xi = inf, yi = inf, xf = -inf, yf = -inf;
    cin >> n;
    for (int i = 1; i <= n; i++)
    {    
        cin >> x[i] >> y[i];
        xi = min(xi, x[i]);
        xf = max(xf, x[i]);
        yi = min(yi, y[i]);
        yf = max(yf, y[i]);
    }
    if (xi == xf || yi == yf)
    {

    }
    for (int i = 1; i <= n; i++)
    {
        if ((x[i] != xi && x[i] != xf) && (y[i] != yi && y[i] != yf))
        {
            puts("NO");
            return ;
        }
    }
    puts("YES");
}

int main() {
 
    int q;
    cin >> q;
    while (q--)
        solve();
    return 0;
}