#include <bits/stdc++.h>
using namespace std;


int main() {
    ios_base::sync_with_stdio(false);

    int q;
    cin >> q;
    while (q--) {
        int n;
        cin >> n;
        vector<pair<int, int>> ver(n);
        int mx_x = -1e4, mn_x = 1e4, mx_y = -1e4, mn_y = 1e4;
        for (int i = 0; i < n; ++i) {
            cin >> ver[i].first >> ver[i].second;
            mx_x = max(mx_x, ver[i].first);
            mn_x = min(mn_x, ver[i].first);
            mx_y = max(mx_y, ver[i].second);
            mn_y = min(mn_y, ver[i].second);
        }

            bool done = true;
            for (int i = 0; i < n; ++i) {
                if (!(((ver[i].first == mn_x || ver[i].first == mx_x) && (ver[i].second >= mn_y && ver[i].second <= mx_y)) ||
                     ((ver[i].first >= mn_x && ver[i].first <= mx_x) && (ver[i].second == mn_y || ver[i].second == mx_y)))) {
                    done = false;
                    break;
                }

            }

            cout << (done? "YES\n" : "NO\n");
    }
    return 0;
}