import itertools

def create_words(word=''):
    perms = set()
    for permutation in itertools.permutations(word):
        prev = ""
        correct = True
        for char in permutation:
            if char == prev:
                correct = False
                break
            prev = char
            
        if correct:
            perms.add("".join(permutation))

    return sorted(list(perms))


if __name__ == "__main__":
    print(create_words("abc")) # ['abc', 'acb', 'bac', 'bca', 'cab', 'cba']
    print(create_words("aab")) # ['aba']
    print(create_words("aaab")) # []

    print(create_words("kala"))
    # ['akal', 'akla', 'alak', 'alka', 'kala', 'laka']

    print(create_words("syksy"))
    # ['ksysy', 'kysys', 'skysy', 'syksy', 'sykys', 'sysky', 
    #  'sysyk', 'yksys', 'ysksy', 'yskys', 'ysyks', 'ysysk']

    print(len(create_words("aybabtu"))) # 660
    print(len(create_words("abcdefgh"))) # 40320