#!/bin/python3

import math
import os
import random
import re
import sys

# Complete the solve function below.
def solve(board):
    res = []
    p_el = None
    flag = False
    for i in board:
        count = 0
        prv = None
        for j in i:
            if count == 0:
                if j == p_el:
                    flag = True
                    break
                else:
                    p_el = j
            count += 1
            if prv == j:
                flag = True
                break
            prv = j
        if flag:
            res.append('No')
            break
    if not flag:
        res.append('Yes')
    return res[0]
        
            
            
if __name__ == '__main__':
    fptr = open(os.environ['OUTPUT_PATH'], 'w')

    t = int(input().strip())

    for t_itr in range(t):
        n = int(input().strip())

        board = []

        for _ in range(n):
            board.append(list(map(int, input().rstrip().split())))

        result = solve(board)

        fptr.write(result + '\n')

    fptr.close()