# Modules and Classes, Includes and Extends

**URL:** <https://www.ruby-forum.com/t/modules-and-classes-includes-and-extends/182611>\
**Category:** Ruby\
**Created:** [January 31, 2010, 12:41am UTC](https://www.ruby-forum.com/t/modules-and-classes-includes-and-extends/182611 "2010-01-31T00:41:56Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![elricstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/da6949/32.png) [@elricstorm](https://www.ruby-forum.com/u/elricstorm)\
**Post date:** [January 31, 2010, 12:41am UTC](https://www.ruby-forum.com/t/modules-and-classes-includes-and-extends/182611/1 "2010-01-31T00:41:56Z")

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I wanted to provide an example which for me is easier to understand than  
always using the Foo + Bar examples others use. When using modules and  
classes, I see them as containers. I decided to just put together a  
more far-fetched example using the Earth, Gravity, Oxygen, and an  
AlienSpecies.

> <https://gist.github.com/anonymous/290785>

I don’t normally nest modules and classes deeply, so I’m just trying to  
wrap my head around the idea of including and extending modules and  
classes.

I believe that I’m correct with the very last example, or am I not?

If you want to add some more examples to this, please do.