import string
import itertools
import random

def gen_pass():
    initial_consonants = (set(string.ascii_lowercase) - set('aeiou')
                        # remove those easily confused with others
                        - set('qxc')
                        # add some crunchy clusters
                        | set(['bl', 'br', 'cl', 'cr', 'dr', 'fl',
                            'fr', 'gl', 'gr', 'pl', 'pr', 'sk',
                            'sl', 'sm', 'sn', 'sp', 'st', 'str',
                            'sw', 'tr'])
                        )

    final_consonants = (set(string.ascii_lowercase) - set('aeiou')
                        # confusable
                        - set('qxcsj')
                        # crunchy clusters
                        | set(['ct', 'ft', 'mp', 'nd', 'ng', 'nk', 'nt',
                                'pt', 'sk', 'sp', 'ss', 'st'])
                        )

    vowels = 'aeiou' # we'll keep this simple

    # each syllable is consonant-vowel-consonant "pronounceable"
    syllables = map(''.join, itertools.product(initial_consonants,
                                                vowels,
                                                initial_consonants,
                                                vowels,
                                                final_consonants))

    return random.sample(syllables, 1)[0]