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

int main() {
   
    unsigned short q;
    cin >> q;
    
    while (q--) {
        unsigned short n;
        cin >> n;
        int x[n], y[n];
        int vx = 0, vy = 0;
        bool ok = true;
        for (int t1 = 0; t1 < n; ++t1) {
            cin >> x[t1] >> y[t1];
            if (t1) {
                if (x[t1] != x[t1-1]) ++vx;
                if (y[t1] != y[t1-1]) ++vy;
            }
        }
        if (vx+vy <= n)
            cout << "YES\n";
        else cout << "NO\n";
    }
    
    
    
    
    
    
    
    
    return 0;
}