import java.awt.Point;
import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class hackerrrrara{

    public static void main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
    Scanner sc  = new Scanner(System.in);
        int q = sc.nextInt();
        for (int i=0; i< q; i++){
             int n = sc.nextInt();
            ArrayList <Point> list = new ArrayList<Point>();
            
            for(int j=0; j< n; j++){    	
            int x = sc.nextInt();
            int y = sc.nextInt();
                Point xy = new Point(x,y);
            	list.add(xy);
        }
            if (check(list)){
            	System.out.println("YES");
            }
            else{
            	System.out.println("NO");
                	
            }
            
         
            }
          
    
    }
    
    public static boolean check( ArrayList <Point> list){
    for(int i=0; i< list.size()-3; i++){
   	 Point A = list.get(i);
   	 Point B = list.get(i+1);
   	 Point C = list.get(i+2);
   	 int a1=(int)A.getX();
   	 int a2=(int)A.getY();
   	 int b1=(int)B.getX();
   	 int b2=(int)B.getY();
   	 int c1=(int)C.getX();
   	 int c2=(int)C.getY();
   	 if( (b1-a1)*(c1-b1)+(b2-a2)*(c2-b2)!=0 ){
   		 return false;
   	 }
    }
	return true;
    }

}