Compute http://xkcd.com/1208/

gistfile1.rb

require 'memoist'

class Footnote
  extend Memoist

  def footnote(statement, number)
    if number == 1
      "Ignore this"
    elsif number == 2
      statement.to_i + 2
    elsif number == 3
      footnote(false, footnote(3, 2))
    elsif number == 4
      false
    elsif number == 5
      footnote(true, footnote(2, footnote(6, 3)))
    elsif number == 6
      footnote(statement, footnote(1, footnote(2, footnote(2))))
    end
  end

  memoize :footnote
end

fn = Footnote.new

puts fn.footnote(true, fn.footnote(1, 2))