#include<bits/stdc++.h>
#define ll long long 
#define pb push_back
#define mp make_pair
#define mod 1000000007
#define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define afor(i,a,b) for(int i=a;i<b;++i)
using namespace std;
 int main()
{
  fast
  ll q,i,j,ans=0;
     cin>>q;
  while(q--)
  {
    ll n,x[11],y[11],l=10000,r=-10000,t=-10000,d=10000;
    cin>>n;
    for(i=0;i<n;i++)
    {
      cin>>x[i]>>y[i];
      if(x[i]>r)
        r=x[i];
      if(x[i]<l)
        l=x[i];
      if(y[i]>t)
        t=y[i];
      if(y[i]<d)
        d=y[i];

    }

   
      ll f=0;
      for(i=0;i<n;i++)
      {
        if(x[i]==l || x[i]==r)
        {
          if(y[i]<d || y[i]>t)
          {
            f=1;
            cout<<"NO\n";
            break;
          }
        }
        else if(y[i]==d || y[i]==t)
        {
          if(x[i]<l || x[i]>r)
          {
            f=1;
            cout<<"NO\n";
            break;
          }
        }
        else
        {
          f=1;
          cout<<"NO\n";
          break;
        }
      }
      if(f==0)
        cout<<"YES\n";
    }
  
  
  return 0;
}