#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    long i,j,t,n,temp; vector <long> x,y,slope;
    cin>>t;
    while(t--)
    {   cin>>n;
        int s=1;
        for(i=0;i<n;i++)
        {   cin>>temp;
            x.push_back(temp);
            cin>>temp;
            y.push_back(temp);
        }
        for(i=0;i<n-1;i++)
        {   if(x[i+1]-x[i]!=0)
                temp=(y[i+1]-y[i])/(x[i+1]-x[i]);
            else
                temp=10001;
            slope.push_back(temp);
        }
        /*for(i=0;i<n-1;i++)
            cout<<slope[i]<<" ";
        cout<<endl;*/
        for(i=0;i<n-2;i++)
        {   for(j=i+1;j<n-1;j++)
            {   if(slope[i]!=slope[j])   
                    s++;
            }
        }
        //cout<<"s = "<<s<<endl;
        if(s>2)
            cout<<"NO\n";
        else if(s==2)
            cout<<"YES\n";
        else
            cout<<"NO\n";
        
    }
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}