#include <bits/stdc++.h>

using namespace std;


#define si(i)                   scanf("%d",&i)
#define si2(i,j)                scanf("%d %d",&i,&j)
#define si3(i,j,k)              scanf("%d %d %d",&i,&j,&k)
#define slli(i)                 scanf("%lld",&i)
#define slli2(i,j)              scanf("%lld %lld",&i,&j)
#define slli3(i,j,k)            scanf("%lld %lld %lld",&i,&j,&k)

#define pi(i)                   printf("%d\n",i)
#define plli(i)                 printf("%lld\n",i)

#define SYNC                    ios_base::sync_with_stdio(0)
#define mp                      make_pair
#define FF                      first
#define SS                      second
#define pb                      push_back
#define fill(a,v)               memset(a,v,sizeof a)
#define ceil(a,b)               (((a)%(b)==0)?((a)/(b)):((a)/(b)+1))
#define rem(a,b)                ((a<0)?((((a)%(b))+(b))%(b)):((a)%(b)))
#define MOD                     1000000007LL
#define INF                     INT_MAX
#define N                       100007


typedef long long int ll;
typedef pair<int,int> PII;
typedef pair<ll,ll> PLL;
typedef vector<string> VS;
typedef vector<int> VI;
typedef vector<ll> VL;
typedef vector<PII> VOII;
typedef vector<PLL> VOLL;
typedef vector<VI> VOVI;

int dX[] = {-1,0,1,0,-1,1,1,-1};
int dY[] = {0,1,0,-1,1,1,-1,-1};





inline void Refresh() {
    
}


int main()
{
    int t;
    cin >> t ;
    while(t--) {
    	int n;
    	int x[15],y[15];
    	int x1,x2,y1,y2;
    	x1 = y1 = INT_MAX;
    	x2 = y2 = INT_MIN;
    	cin >> n;
    	for (int i = 0; i < n; ++i) {
    		cin >> x[i] >> y[i];
    		x1 = min(x1,x[i]);
    		x2 = max(x2,x[i]);
    		y1 = min(y1,y[i]);
    		y2 = max(y2,y[i]);
    	}
        bool flag = true;
    	for (int i = 0; i < n; ++i) {
    		if(!(x[i] == x1 || x[i] == x2 || y[i] == y1 || y[i] == y2)) {
    			cout << "NO" << endl;
    			flag = false;
    		    break;
            }
    	}
        if(!flag) continue;
    	cout << "YES" << endl;
    }
    return 0;
}