Excellent definition.

Also, a class can inherit multiple modules. witness:

```ruby
module Calcable
  def multiply(x, y)
    x + y
  end
end

module FortyTwo
  def multiply(x,y)
    42
  end
end

class Device
  include Calcable
  include FortyTwo
end

Device.new.multiply(5, 20)
```

Check out here for the answer: http://rubyfiddle.com/riddles/3b96d