use std::io;
use std::io::prelude::*;

use std::collections::HashSet;

fn main() {
    let stdin = io::stdin();
    let mut stdin_it = stdin.lock().lines();

    let num_of_queries = stdin_it.next().unwrap().unwrap().parse::<usize>().unwrap();
    for _ in 0 .. num_of_queries {
        let n = stdin_it.next().unwrap().unwrap().parse::<usize>().unwrap();
        let mut points = Vec::new();
        for _ in 0 .. n {
            let line = stdin_it.next().unwrap().unwrap();
            let mut it = line.split_whitespace().map(|x| x.parse::<i32>().unwrap());
            let (x, y) = (it.next().unwrap(), it.next().unwrap());
            points.push((x, y));
        }
        let x_min = points.iter().cloned().map(|p| p.0).min().unwrap();
        let x_max = points.iter().cloned().map(|p| p.0).max().unwrap();
        let y_min = points.iter().cloned().map(|p| p.1).min().unwrap();
        let y_max = points.iter().cloned().map(|p| p.1).max().unwrap();

        if points.into_iter().all(|p| p.0 == x_min || p.0 == x_max || p.1 == y_min || p.1 == y_max) {
            println!("YES");
        } else {
            println!("NO");
        }
    }
}