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


int main() {
    int i, j, k, it, z, n, q, x[15], y[15];
    int my = -1e9, miy = 1e9;
    int mx = -1e9, mix = 1e9;
    for(cin >> q; q; --q) {
        cin >> n;
        my = mx = -1e9;
        miy = mix =  1e9;
        for(i = 1; i <= n; ++i) cin >> x[i] >> y[i], my = max(my, y[i]), miy = min(miy, y[i]), mx = max(mx, x[i]), mix = min(mix, x[i]);
        
        bool ok = 1;
        
        for(i = 1; i <= n && ok; ++i)
            for(j = 1; j <= n && ok; ++j)
                for(k = 1; k <= n && ok; ++k)
                    for(it = 1; it <= n && ok; ++it) {
                        if(i ==j || i == k || i == it) continue;
            if(j == k || j == it) continue;
            if(it == k) continue;
            if(x[i] < x[j] && x[it] > x[i] && x[it] < x[j] && y[j] < y[k] && y[j] < y[it] && y[k] > y[it]) ok = 0;
            if(x[i] < x[j] && x[it] > x[i] && x[it] < x[j] && miy < y[it] && my > y[it]) ok = 0;
            if(mix < x[it] && mx > x[it] && miy < y[it] && my > y[it]) ok = 0;
                    }

        for(i = 1; i <= n && ok; ++i) if(mix < x[i] && mx > x[i] && miy < y[i] && my > y[i]) ok = 0;
        
        cout << (ok ? "YES" : "NO") << '\n';
    }
    return 0;
}