using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace rect
{
    class Program
    {
        static void Main(string[] args)
        {
            int nCases = int.Parse(Console.ReadLine());

            for (int nCase = 0; nCase < nCases; nCase++)
            {
                string answer = "NO";

                int numberOfPoints = int.Parse(Console.ReadLine());

                var points = new List<int[]>();

                int minX = int.MaxValue, minY = int.MaxValue, maxX = int.MinValue, maxY = int.MinValue;

                for (int i = 0; i < numberOfPoints; i++)
                {

                    int[] point = Array.ConvertAll(Console.ReadLine().Split(' '), int.Parse);

                    if (minX > point[0])
                    {
                        minX = point[0];
                    }
                    if (maxX < point[0])
                    {
                        maxX = point[0];
                    }


                    if (minY > point[1])
                    {
                        minY = point[1];
                    }
                    if (maxY < point[1])
                    {
                        maxY = point[1];
                    }

                    points.Add(point);
                }

                int pointsOK=0;

                for (int pointIndex = 0; pointIndex < points.Count; pointIndex++)
                {
                    if (points[pointIndex][0] == maxX)
                    {
                        if (points[pointIndex][1] >= minY || points[pointIndex][1] <= minY)
                        {
                            pointsOK++;
                        }
                    }
                    else if (points[pointIndex][0] == minX)
                    {
                        if (points[pointIndex][1] >= minY || points[pointIndex][1] <= minY)
                        {
                            pointsOK++;
                        }
                    }
                    else if (points[pointIndex][1] == maxY)
                    {
                        if (points[pointIndex][0] >= minX || points[pointIndex][0] <= minX)
                        {
                            pointsOK++;
                        }
                    }
                    else if (points[pointIndex][1] == minY)
                    {
                        if (points[pointIndex][0] >= minX || points[pointIndex][0] <= minX)
                        {
                            pointsOK++;
                        }
                    }
                    else
                    {
                        break;
                    }
                }

                if (pointsOK == points.Count)
                {
                    answer = "YES";
                }
                

                Console.WriteLine(answer);
            }

        }
    }
}