gen.py

#!/usr/local/bin/python3

def generate(chars, current = ''):
    for index,char in enumerate(chars):
        joined = current + char
        yield joined

        for word in generate([
            char for i,char in enumerate(chars) if i != index
        ],joined):
            yield word

chars = [
    'a',
    'b',
    'c',
    'd',
    'e',
    'f',
    't',
    't'
];

dictionary = set([
    'tea',
    'eat',
    'teat',
    'meat',
    'mate',
    'date',
    'fate'
    'feat'
])


words = [word for word in generate(chars) if word in dictionary]

count = 0
for word in words:
    count += 1
    print(word)