module Car
  def vroom
    '<car noise>'
  end
end

module Boat
  def vroom
    '<boat noise>'
  end
end

module Enhancer
  def vroom
    "<enhanced #{super}>"
  end
end

class CarBoat
  include Car
  include Boat
end

class BoatCar
  include Boat
  include Car
end

class EnhancedCar
  include Car
  include Enhancer
end

puts BoatCar.new.vroom
puts CarBoat.new.vroom
puts EnhancedCar.new.vroom

###

<car noise>
<boat noise>
<enhanced <car noise>>