gistfile1.rb

class BaseWall
  def self.Wall length, width, material
    Module.new do
      define_method(:length) { length }
      define_method(:width) { width }
      define_method(:material) { material }

      def self.included clazz
        private :length, :width, :material
      end
    end
  end

  def dimensions
    "I am #{length}ft. long and #{width}ft. wide!"
  end

  def made_from
    "I am made from #{material}!"
  end
end

class BrickWall < BaseWall
  include Wall(30, 20, 'brick')
end

class ConcreteWall < BaseWall
  include Wall(30, 20, 'concrete')
end

class WoodWall < BaseWall
  include Wall(10, 20, 'wood')
end