#include <bits/stdc++.h>
#include<string.h>
#define MAX 1000005
#define MOD 1000000007
#define MA 1200000
#define PI 3.14159265358979323846264338327950
//const int  MAXA=1e15+1;
typedef long long int  ll;
const int INF=1e18;
using namespace std;
const int maxn=1e5+5;
const int ma=1e9+5;
int x[15],y[15];
int main()
{
    //freopen("input.txt","r+",stdin);
    //freopen("output.txt","w+",stdout);
    ios::sync_with_stdio(0);
    cin.tie(0);
    int t,n,i;
    cin>>t;
    while(t--)
    {
        cin>>n;
        int f=0,minx=INT_MAX,miny=INT_MAX,maxx=INT_MIN,maxy=INT_MIN;
        for(i=0;i<n;i++)
        {
            cin>>x[i]>>y[i];
            minx=min(minx,x[i]);
            maxx=max(maxx,x[i]);
            miny=min(miny,y[i]);
            maxy=max(maxy,y[i]);
        }
        for(i=0;i<n;i++)
        {
            if(x[i]==minx||x[i]==maxx||y[i]==miny||y[i]==maxy)
            {
                if(x[i]==minx)
                {
                    if(y[i]<miny||y[i]>maxy)
                        f=1;
                }
                else if(x[i]==maxx)
                {
                    if(y[i]<miny||y[i]>maxy)
                        f=1;
                }
                else if(y[i]==miny)
                {
                    if(x[i]<minx||x[i]>maxx)
                        f=1;
                }
                else if(y[i]==maxy)
                {
                    if(x[i]<minx||x[i]>maxx)
                        f=1;
                }
                else
                    f=1;
            }
            else
                f=1;

        }
        if(f)
            printf("NO\n");
        else
            printf("YES\n");
    }
    return 0;
}