#include<bits/stdc++.h>
#define I int 
#define li long 
using namespace std;

int main()
{
    int Q;
    cin>>Q;
    
    while(Q--)
    {
        int N,i,j;
        cin>>N;
        
        vector<li>V1(N);
        vector<li>V2(N);
        vector<li>V;
        
        for(i=0;i<=N-1;i++)
        {
            cin>>V1[i]>>V2[i];
        }
        
        for(i=0;i<=N-2;i++)
        {
            for(j=i+1;j<=N-1;j++)
            {
                if(V1[i]==V1[j])
                {
                    V.push_back(1000000);
                }    
                else
                {
                    V.push_back((V2[j]-V2[i])/(V1[j]-V1[i]));
                }    
            }    
        }
        
        sort(V.begin(),V.end());
        
        int Count=0;
        for(i=0;i<=N-2;i++)
        {
            if(V[i]!=V[i+1])
            {
                Count++;
            }    
        }    
        
        
        if(Count==2)
        {
            cout<<"YES\n";
        }
        else
        {
            cout<<"NO\n";
        }
        
    }
    
    
 return 0;   
}