#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
struct point 
    {
    int x;
    int y;
};
typedef struct point pt;
    bool compare1(pt a,pt b)
    {
    return a.x<b.x;
}
bool compare2(pt a,pt b)
    {
    return a.y<b.y;
}
bool equal(pt a,pt b)
    {
    if(a.x==b.x&&a.y==b.y)
        return true;
    else
        return false;
}

void solve()
    {
    int n;
    cin>>n;
    int x,y,i;
   // cin>>x>>y;
    int a,b,flag=0;
        pt arr[n],brr[n];
    float sa,sb,sc,sd;
    for(i=0;i<n;i++)
        {
        cin>>a>>b;
        arr[i].x=a;
        arr[i].y=b;
        brr[i].x=a;
        brr[i].y=b;
        
    }
    sort(arr,arr+n,compare1);
    sort(brr,brr+n,compare2);
    if(arr[0].y==arr[n-1].y&&brr[0].x==brr[n-1].x&&equal(arr[0],brr[0]))
        {
        flag=0;
        for(i=1;i<n-1;i++)
            {
            if(arr[i].x!=arr[0].x&&arr[i].x!=arr[n-1].x)
                flag=1;
            if(arr[i].y!=brr[0].y&&arr[i].y!=brr[n-1].y)
                flag=1;
        }
        if(flag==0)
            cout<<"YES\n";
        else
            cout<<"NO\n";
        return;
        
    }
        
    if(arr[0].x!=brr[0].x)
     sa=(arr[0].y-brr[0].y)/(arr[0].x-brr[0].x);
    if(arr[0].x!=brr[n-1].x)
     sb=(arr[0].y-brr[n-1].y)/(arr[0].x-brr[n-1].x);  
    if(sa*sb!=-1)
        {
        cout<<"NO\n";return;
    }
    else
        {
        if(arr[n-1].x!=brr[0].x)
    sc=(arr[n-1].y-brr[0].y)/(arr[n-1].x-brr[0].x);
    if(arr[n-1].x!=brr[n-1].x)
 sd=(arr[n-1].y-brr[n-1].y)/(arr[n-1].x-brr[n-1].x); 
        if(sc*sd!=-1)
            {
             cout<<"NO\n";return;
        }
       double d1=sqrt(pow((brr[0].x-arr[0].x),2)+pow((brr[0].y-arr[0].y),2));
        double d2=sqrt(pow((brr[0].x-arr[n-1].x),2)+pow((brr[0].y-arr[n-1].y),2));
        double d3=sqrt(pow((brr[n-1].x-arr[0].x),2)+pow((brr[n-1].y-arr[0].y),2));
       double d4=sqrt(pow((brr[n-1].x-arr[n-1].x),2)+pow((brr[n-1].y-arr[n-1].y),2)); 
        if(d1!=d4||d2!=d3)
            {
             cout<<"NO\n";return;
        }
        flag=0;
       /* for(i=1;i<n-1;i++)
            {
            if(!collinear(arr[i],arr[n-1],brr[0])&&!collinear(arr[i],arr[0],brr[0])&&!collinear(arr[i],arr[0],brr[n-1])&&!collinear(arr[i],arr[n-1],brr[n-1]))
                flag=1;
        }
    
        if(flag==0)
            cout<<"YES\n";
        else
            cout<<"NO\n";*/
    
}
    
}
int main() {
    int t;
    cin>>t;
    while(t--)
        solve();
    return 0;
}