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

public class Solution {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int q = sc.nextInt();
        while(q>0)
        {
            int n = sc.nextInt();
            List<point> points = new ArrayList<>();
            for(int i=0;i<n;i++)
                {
                point p = new point(sc.nextInt(), sc.nextInt());
                points.add(p);
            }
            int max_x = -1000000;
            int max_y = -1000000;
            int min_x =  1000000;
            int min_y =  1000000;
            
            for(point p :points)
                {
                max_x = Math.max(max_x, p.x);
                max_y = Math.max(max_y,p.y);
                min_x = Math.min(min_x, p.x);
                min_y = Math.min(min_y,p.y);          
            }
            
             for(point p :points)
                {
                max_x = Math.max(max_x, p.x);
                max_y = Math.max(max_y,p.y);
                min_x = Math.min(min_x, p.x);
                min_y = Math.min(min_y,p.y);          
            }
            boolean b = true;
             for(point p :points)
             {
               if(p.x == min_x || p.x ==max_x || p.y == max_y || p.y ==min_y)
                   continue;
                 else
                     {
                   b = false;
                     break;
                 }
                   
            }
            
            if(b)
                System.out.println("YES");
            else
                 System.out.println("NO");
            q--;
        }
    }
    
    static class point
        {
        int x;
        int y;
        public point (int x, int y)
           {
            this.x = x;
            this.y = y;
        }
    }
}