Here is my solution, just one Deck class, no guessing:
###
class Deck
def initialize
@deck = Array.new(54) {|i| i}
end
def create_keystream(count)
stream = []
count.times do
letter = next_letter
redo unless letter
stream << letter
end
return stream
end
def next_letter
##
# move the jokers
##
2.times do |j|
# find the joker
index = @deck.index(52 + j)
# remove it from the deck
@deck.delete_at(index)
# calculate new index
index = ((index + j) % 53) + 1
# insert the joker at that index
@deck[index, 0] = 52 + j
end
##
# do the tripple cut
##
# first find both jokers
a = @deck.index(52)
b = @deck.index(53)
# sort the two indeces
low, hi = [a, b].sort
# get the lower and upper parts of the deck
upper = @deck.slice!((hi + 1)..-1)
lower = @deck.slice!(0, low)
# swap them
@deck = upper + @deck + lower
##
# do the count cut
##
# find out the number of cards to cut
count = value_at(53)
# remove them from the top of the deck
cards = @deck.slice!(0, count)
# reinsert them just above the lowest card
@deck[-1, 0] = cards
return letter_at(value_at(0))
end
def value_at(index)
id = @deck[index]
(id > 51) ? 53 : id + 1
end
def letter_at(index)
id = @deck[index]
(id > 51) ? nil : (id % 26) + 1
end
def to_s
@deck.map {|v| (v > 51) ? (v + 13).chr : (v + 1).to_s}.join(' ')
end
end
def encode(data, keystream)
result = []
data.size.times {|i| result << ((data
+ keystream) % 26)}
return result
end
def decode(data, keystream)
encode(data, keystream.map {|v| 26 - v})
end
def data_to_string(data)
data = data.map {|v| (v + 65).chr}.join
(0...(data.size / 5)).map {|i| data[i * 5, 5]}.join(' ')
end
if ARGV.size != 1
puts "Usage: solitaire.rb MESSAGE"
exit
end
data = ARGV[0].upcase.split(//).select {|c| c =~ /[A-Z]/}.map {|c| c[0] -
65}
data += [?X - 65] * (4 - (data.size + 4) % 5)
deck = Deck.new
keystream = deck.create_keystream(data.size)
puts 'encoded:', data_to_string(encode(data, keystream))
puts 'decoded:', data_to_string(decode(data, keystream))
###
That was fun to code 
