import java.io.*;
import java.util.*;
import java.math.BigInteger;
public class Solution {

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        int q = input.nextInt();
        for(int i=0;i<q;i++)
        {
        int n = input.nextInt();
       int arr[][] = new int[n][2];
                arr[0][0] = input.nextInt();
             arr[0][1] = input.nextInt();
        int maxx = -10000-5;
        int maxy = -10000-5;
        
       for(int j=1;j<n;j++)
        {
            for(int jk=0;jk<2;jk++)
            {
                arr[j][jk] = input.nextInt();
                if(jk==0)
                {arr[j][jk] = arr[j][jk] - arr[0][0];
                  
                }
                else
                {
                    arr[j][jk] = arr[j][jk] - arr[0][1];
                  
                }
                }
            if(arr[j][0] == 0)
            {
                if(arr[j][1]>maxy)
                    maxy = arr[j][1];
            }
            if(arr[j][1] == 0)
            {
                if(arr[j][0]>maxx)
                    maxx = arr[j][1];
            }
        }
        arr[0][0] = 0;
        arr[0][1] = 0;
        boolean flag = false;
        for(int jk=0;jk<n;jk++)
        {
            if(arr[jk][0]!=0 && arr[jk][1]!=0 && arr[jk][0]<maxx )
            {
                flag =true;
                break;
            }
          if(arr[jk][0]!=0 && arr[jk][1]!=0 && arr[jk][1]<maxy )
            {
                flag =true;
                 break;
            }

        
        }
        if(!flag)System.out.println("YES");
        else
                System.out.println("NO");
        }  /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
    }
}