http://blog.guiltry.com/difference-between-simple-factory-and-factory-method-pattern/

simple_factory.rb

class Factory::User
  def self.make_user(user_type)
    
    if user_type == "Knight"
      @user = Knight.new
      # Do some Knight specific operation
    elsif user_type == "Archer"
      @user = Archer.new
      # Do some Archer specific operation
    end

    return @user
  end
end