#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
struct Point
{
    double x,y;
    Point (double x,double y)
    {
        x=x;y=y;
    }
    Point()
        {
        x=y=0;
    }
};
double operator * (Point p1,Point p2)
{
    return (p1.x*p2.y-p2.x*p1.y);
}
Point operator - (Point p1, Point p2) 
{
    return Point(p1.x-p2.x, p1.y-p2.y);
}
bool prin(Point a,Point b,Point c,Point p)
{
    double s1=((a-b)*(c-b)/2),s2=((a-p)*(c-p)/2)+((b-p)*(c-p)/2)+((a-p)*(b-p)/2);
    if (fabs(s2-s1)<0.00001) return 1;
    else return 0;
}
int main() 
{
    long long q;
    cin>>q;
    while(q>0)
    {
        long long n;
        cin>>n;
        Point p[n];
        for (int i=0;i<n;i++)
        {
            cin>>p[i].x>>p[i].y;
        }
        q--;
        bool was=0;
        for (int i=0;i<n;i++)
        {
            for (int j=i+1;j<n;j++)
            {
                for (int x=j+1;x<n;x++)
                {
                    for (int uk=0;uk<n;uk++)
                    {
                       if (!(prin(p[uk],p[i],p[j],p[x])))
                       {
                           cout<<"NO";
                           was=1;
                           break;
                       }
                    }
                    if (was) break;
                }
                if (was) break;
            }
            if (was) break;
        }
        if (was==0)cout<<"YES";
        cout<<"\n";
    }
    return 0;
}