# File lib/quiz1/t/solutions/Moses Hohman/cipher.rb, line 74
                def initialize(text, deck=Deck.new)
                        @chunker = Chunker.new(text)
                        keystream = Keystream.new(deck)
                        @keystream_chunker = Chunker.new(keystream.keystream_letters(@chunker.chunks).join)
                        if text =~ ENCRYPTED_TEXT_PATTERN
                                @mode = "decrypt"
                                @calc_number = proc { |num, keystream_num| num - keystream_num }
                        else
                                @mode = "encrypt"
                                @calc_number = proc { |num, keystream_num| num + keystream_num }
                        end
                end