#!/bin/python

line = int(raw_input())
blist = []

for i in range(line):
    size = int(raw_input());
    clist =[]
    for j in range(size):
        alist = raw_input().split()
        clist.append(alist)
        
        for k in range(len(clist)-1):
            if clist[k] == clist[k+1]:
                print "No"
                break;
            else:
                for h in range(len(clist[k])-1):
                    if clist[k][h] == clist[k][h+1]:
                        print "No"
                else:
                    print "Yes"