#include<bits/stdc++.h>
#define mp make_pair
#define PII pair<int,int>
#define fi first
#define se second
#define pb push_back
using namespace std;

//********************************************
//Error tracking
#define show(args...) { vector<string> _v = split(#args, ','); err(_v.begin(), args); }

vector<string> split(const string& s, char c) {
    vector<string> v;
    stringstream ss(s);
    string x;
    while (getline(ss, x, c))
        v.emplace_back(x);
    return move(v);
}

void err(vector<string>::iterator it) {}
template<typename T, typename... Args>
void err(vector<string>::iterator it, T a, Args... args) {
    cerr << it -> substr((*it)[0] == ' ', it -> length()) << " = " << a << '\n';
    err(++it, args...);
}
//********************************************

const int NMAX = 15;

int q,n;
PII a[NMAX];
int mn[5],mx[5];

int main()
{
    int i;

    //freopen("input","r",stdin);
   // freopen("output","w",stdout);
    cin.sync_with_stdio(false);

    cin >> q;
    while (q--)
    {
        cin >> n;

        mx[0] = mx[1] = -(1<<30);
        mn[0] = mn[1] = 1<<30;
        for (i = 1; i <= n; i++)
        {
            cin >> a[i].fi >> a[i].se;

            mn[0] = min(mn[0],a[i].fi);
            mx[0] = max(mx[0],a[i].fi);
            mn[1] = min(mn[1],a[i].se);
            mx[1] = max(mx[1],a[i].se); 
        }

        int ok = 1;
        for (i = 1;i <= n; i++)
        {
            PII x = a[i];
            if (mn[0] < x.fi && x.fi < mx[0] && mn[1] < x.se && x.se < mx[1]) ok = 0;
        }

       //if (mn[0] == mx[0] && mn[1] == mx[1]) ok = 0;

        if (ok == 1) cout << "YES\n";
        else cout << "NO\n";
    }
    return 0;   
}