/*
ye mera template hai
apna khud likho bc :P
*/

/*
Author : Sarvagya Agarwal
*/

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

//defines
#define openin freopen("input.txt","r",stdin)
#define openout freopen("output.txt","w",stdout)
#define fast ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
#define ll long long
#define int long long
#define mod 1000000007
#define rep(i,x,y) for (__typeof(x) i=x;i<=y;i++)
#define all(c) (c).begin(),(c).end()
#define ff first
#define ss second
#define pb push_back
#define mp make_pair

int power(int a , int b)
{
    int res = 1 ;
    while(b)
    {
        if(b%2) {
            res = (res * a)%mod ;
        }
        b/=2 ;
        a = (a*a)%mod ;
    }
    return res ;
}

//debug
#define TRACE

#ifdef TRACE
#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1>
void __f(const char* name, Arg1&& arg1){
		cerr << name << " : " << arg1 << std::endl;
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args){
		const char* comma = strchr(names + 1, ',');cerr.write(names, comma - names) << " : " << arg1<<" | ";__f(comma+1, args...);
}
#else
#define trace(...)
#endif
struct point{ 
    int x,y ;
};
vector<point> v ;
int32_t main()
{
    fast;
    int q ;
    cin >> q ;
    while(q--)
    {
        int n ;
        cin >> n ;
        v.clear() ;
        rep(i,1,n)
        {
            point temp ;
            cin >> temp.x >> temp.y ;
            v.pb(temp) ;
        }
        int x1=1e5,y1=1e5,x2=-1e5,y2=-1e5 ;
        for(auto it : v) {
            x1 = min(x1,it.x) ;
            x2 = max(x2,it.x) ;
            y1 = min(y1,it.y) ;
            y2 = max(y2,it.y) ;
        }
        string ans = "YES" ;
        for(auto it : v) {
            if(it.x != x1 && it.x!=x2 && it.y != y1 && it.y != y2) {
                ans = "NO" ;
                break;
            }
        }
        cout << ans << endl;
    }
    return 0;
}