import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Solution {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		
		Scanner s = new Scanner(System.in);
		int q = s.nextInt();
		while(q > 0){
			q--;
			int n = s.nextInt();
			int minX = Integer.MAX_VALUE;
			int maxX = Integer.MIN_VALUE;
			int minY = Integer.MAX_VALUE;
			int maxY = Integer.MIN_VALUE;
			boolean output = true;
			boolean edgeX = true;
			boolean edgeY = true;
			boolean present = true;
			
			List<Integer> X = new ArrayList<>();
			List<Integer> Y = new ArrayList<>();
			
			for(int i = 0; i< n;i++){
				int x = s.nextInt();
				int y = s.nextInt();

				X.add(x);
				Y.add(y);
				
				if(x < minX){
					minX = x;
				}
				if(x > maxX){
					maxX = x;
				}
				if(y < minY){
					minY = y;
				}
				if(y > maxY){
					maxY = y;
				}
			}

			for(int i = 0; i< n; i++){
				int x = X.get(i);
				int y = Y.get(i);
				edgeX = false;
				edgeY = false;
				present = false;
				if(x == minX || x ==maxX)
					edgeX = true;
				
				if(y == minY || y ==maxY)
					edgeY = true;
				
				if(edgeX || edgeY)
					present = true;
				
				if(!present){
					output = false;
					break;
				}
			}
			
			if(output){
				System.out.println("YES");
			}
			else{
				System.out.println("NO");
			}

		}
		
	}
}