t = int(input())

for _ in range(t):
    n = int(input())
    s = input().split()

    ok = True
    for i in range(n):
        base = 5 * i
        x1 = s[base]
        x2 = s[base + 1]
        x3 = s[base + 2]
        x4 = s[base + 3]
        x5 = s[base + 4]

        if not (x1 == x3 and x2 == x4 and x2 == x5 and x1 != x2):
            ok = False
            break

    print('Yes' if ok else 'No')