/*
* @Author: manumeral
* @Date:   2016-10-18 21:45:06
* @Last Modified by:   manumeral
* @Last Modified time: 2016-10-18 23:23:54
*/

#include <bits/stdc++.h>
using namespace std;
#define lli long long int
#define infinite numeric_limits<lli>::max()
#define fr(i,j,s) for(i = j ; i < s ; i++)
#define ifr(i,j,s) for(i = j ; i >= s ; i--)
#define MOD 1000000007
#define PI 3.141592653589793
#define pb(i) push_back(i)
#define all(x) x.begin(),x.end()
#define sz(a) ((a.size()))
#define sqr(x) ((x)*(x))
#define mp(i,j) make_pair(i,j)
#define clr clear()
#define ins insert
#define xx first
#define yy second
lli binomialCoeff(lli n, lli k)
{
    lli C[n+1][k+1];
    lli i, j;
    fr(i,0,n+1)
    {
        fr(j,0,(min(i, k)+1))
        {   
            if (j == 0 || j == i)
                C[i][j] = 1;
            else
                C[i][j] = C[i-1][j-1] + C[i-1][j];
        }
    }
    return C[n][k];
}
vector<bool> natural_nos(100001,true);//10^5
vector<lli> prime ;
void precompute()
{
    lli i,j;
    fr(i,2,100001)
    {
        prime.pb(i);
        for(j=2;(j*i<100001)&&(natural_nos[i]);j++)
        {
            natural_nos[j*i]=false;
        }
    }
}
bool comp3(pair<lli,lli> &a,pair<lli,lli> &b)
{
    if(b.yy!=a.yy)
        return b.yy<a.yy;
    else
        return b.xx<a.xx ;
}   
bool comp(pair<lli,lli> &a,pair<lli,lli> &b)
{
    if(b.xx!=a.xx)
        return b.xx<a.xx;
    else
        return b.yy>a.yy ;
}   
bool comp2(pair<lli,lli> &a,pair<lli,lli> &b)
{
    if(b.yy!=a.yy)
        return b.yy>a.yy;
    else
        return b.xx>a.xx ;
}   
int main(void)
{
    ios_base::sync_with_stdio(0);
    lli test,i,j,k,n,m,a,b,temp1,temp2,temp3,ans;
    cin>>test;
    vector<pair<lli,lli> > A; 
    pair<lli,lli> a1,a2,a3,a4,a5,a6,a7,a8;
    set<pair<lli,lli> > st;
    while(test--)
    {
        cin>>n;
        A.clear();
        st.clear();
        fr(i,0,n)
        {
            cin>>a>>b;
            A.pb(mp(a,b));
        }
        
        sort(all(A));
        temp1 = A[0].xx ;
        i=0 ;
        while(i<n&&A[i].xx==temp1)
        {    
            st.insert(A[i]);
            i++;
        }
        a1 = A[i-1] ;
        a2 =A[0];
        
        sort(all(A),comp);
        temp1 = A[0].xx ;
        i=0 ;
        while(i<n&&A[i].xx==temp1)
        {    
            st.insert(A[i]);
            i++;
        }
        a5=A[0];
        a6=A[i-1];
        
        sort(all(A),comp2);
        temp1 = A[0].yy ;
        i=0 ;
        while(i<n&&A[i].yy==temp1)
        {    
            st.insert(A[i]);
            i++;
        }
        a3=A[0];
        a4=A[i-1];
        
        sort(all(A),comp3);
        temp1 = A[0].yy ;
        i=0 ;
        while(i<n&&A[i].yy==temp1)
        {    
            st.insert(A[i]);
            i++;
        };
        a7=A[0];
        a8=A[i-1];
        if(a1.yy<=a8.yy&&a8.xx>=a1.xx&&a6.yy<=a7.yy&&a6.xx>=a7.xx&&a5.xx>=a4.xx&&a4.yy<=a5.yy&&a2.xx<=a3.xx&&a3.yy<=a2.yy)
        {
            bool check = true;
            fr(i,0,n)
            {
                if(st.find(A[i])==st.end())
                {
                    check =false ;
                }
            }
            if(!check)
                cout<<"NO"<<endl;
            else
                cout<<"YES"<<endl;
        
        }
        else
            cout<<"NO"<<endl;
    }
    return 0;
}