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

int n;
pair < int, int > a[111];
#define F first
#define S second

int main() {
    int t;
    cin >> t;
    while (t--) {
        cin >> n;
        a[0] = make_pair(111111, 111111);
        a[n + 1] = make_pair(-111111, -111111);
        for (int i = 1; i <= n; ++i) {
            cin >> a[i].F >> a[i].S;            
            a[n + 1].F = max(a[n + 1].F, a[i].F);
            a[0].F = min(a[0].F, a[i].F);
            a[n + 1].S = max(a[n + 1].S, a[i].S);
            a[0].S = min(a[0].S, a[i].S);
        }
        bool ok = 1;
        for (int i = 1; i <= n; ++i) {
            if (!(((a[i].S == a[0].S || a[i].S == a[n + 1].S) && (a[0].F <= a[i].F && a[i].F <= a[n + 1].F)) || ((a[i].F == a[0].F || a[i].F == a[n + 1].F) && (a[0].S <= a[i].S && a[i].S <= a[n + 1].S))))
                ok = 0;
        }
        cout << (ok ? "YES" : "NO") << "\n";
    }
    
    return 0;
}