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();
        
        for (int q = 0; q < Q; q++) {
            int n = sc.nextInt();
            List<Coordinate> points = new ArrayList<>();
            for (int i = 0; i < n; i++) {
                points.add(new Coordinate(sc.nextInt(), sc.nextInt()));
            }
            System.out.println(solution(points));
        }
    }
    
    public static String solution(List<Coordinate> points) {
        Rectangle rect = new Rectangle(getTop(points), getRight(points), getBottom(points), getLeft(points));
        for (Coordinate point: points) {
            if (!rect.hasInBorder(point)) return "NO";
        }
        return "YES";
    }
    
    public static Coordinate getTop(List<Coordinate> points) {
        Coordinate top = points.get(0);
        for (Coordinate point: points) {
            if (point.y > top.y) top = point;
        }
        return top;
    }
    
    public static Coordinate getRight(List<Coordinate> points) {
        Coordinate right = points.get(0);
        for (Coordinate point: points) {
            if (point.x > right.x) right = point;
        }
        return right;
    }
    
    public static Coordinate getBottom(List<Coordinate> points) {
        Coordinate bottom = points.get(0);
        for (Coordinate point: points) {
            if (point.y < bottom.y) bottom = point;
        }
        return bottom;
    }
    
    public static Coordinate getLeft(List<Coordinate> points) {
        Coordinate left = points.get(0);
        for (Coordinate point: points) {
            if (point.x < left.x) left = point;
        }
        return left;
    }
    
    public static class Rectangle {
        public final Coordinate top;
        public final Coordinate right;
        public final Coordinate bottom;
        public final Coordinate left;
        
        public Rectangle(Coordinate top, Coordinate right, Coordinate bottom, Coordinate left) {
            this.top = top;
            this.right = right;
            this.bottom = bottom;
            this.left = left;
        }
        
        public boolean hasInBorder(Coordinate p) {
            return ((p.x == left.x || p.x == right.x) && (bottom.y <= p.y && p.y <= top.y)) 
                || ((p.y == bottom.y || p.y == top.y) && (left.x <= p.x && p.x <= right.x));
        } 
    }
    
    public static class Coordinate {
        public final int x;
        public final int y;
        public Coordinate(int x, int y) {
            this.x = x;
            this.y = y;
        }
    }
}