a joke example of refinements.

husband.rb

class Husband
  attr_accessor :affair
  def say
    puts "I love my wife."
  end
end

module Secret
  refine Husband do
    def say
      if @affair
        puts "I love #{@affair}."
      else
        super
      end
    end
  end
end

love_nest.rb

require_relative "husband"

using Secret

man = Husband.new
man.affair = "Beth"

puts "in the love nest"
man.say # => "I love Beth."

public_space.rb

require_relative "husband"

man = Husband.new
man.affair = "Beth"

puts "In public space"
man.say # => "I love my wife."