/*********                      Muntasher Morshed                     *********/
/*********                            Submit                          *********/
/*********                  University of Asia Pacific                *********/

#include<bits/stdc++.h>

#define sf scanf
#define sf1(a) scanf("%d",&a)
#define sf2(a,b) scanf("%d %d",&a,&b)
#define pf printf
#define pfC(ca) printf("Case %d: ",ca)
#define li long int
#define lli long long int
#define ll long long
#define loop0(i,n) for(i=0; i<n; i++)
#define loop1(i,n) for(i=1; i<=n; i++)
#define rloop0(i,n) for(i=n-1; i>=0; i--)
#define rloop1(i,n) for(i=n; i>0; i--)
#define maxn 100000
#define pi1 3.1415926535897932385
#define pi2 2*(acos(0.0))
#define pb push_back
#define fill(a,val) memset(a,val,sizeof(a))
using namespace std;
int main()
{
    int t,n,x,y;
    sf1(t);
    while(t--)
    {
        bool f1=false,f2=false,f3=false,f4=false;
        bool final=true;
        sf1(n);
        int xmax=-999999,xmin=99999999,ymax=-9999999,ymin=9999999;
        while(n--)
        {
            sf2(x,y);
            if(f1==false && f2==false && x<xmin && x>xmax)
            {
                xmin=x;
                xmax=x;
                f1=true;
            }
            if(f1==true && f2!=true && x!=xmin)
            {
                xmax=x;
                f2=true;
            }
            if(f3==false && f4==false && y<ymin && y>ymax)
            {
                ymin=y;
                ymax=y;
                f3=true;
            }
            if(f3==true && f4==false && y!=ymin)
            {
                ymax=y;
                f4=true;
            }
            if(x!=xmax)
                if(x!=xmin)
                    final=false;
            if(y!=ymax)
                if(y!=ymin)
                    final=false;
        }
        if(final==false)
            cout<<"NO"<<endl;
        else
            cout<<"Yes"<<endl;
    }
    return 0;
}