The Sitecore Helix methodology has been implemented in an example solution - actually the exact one you are browsing right now.
This example solution with full source code and a set of simple to use tools are available for your use on github.com. Please follow the link below to find the repository.
In the Sitecore Habitat GitHub wiki you will find information on how to install and work with the example implementation. You can also click around in the Modules section of this site to see which modules are included in the example.
Good luck with Helix and Habitat!