Hello Unity is a remarkable application that makes easy the understanding of how a custom app can be integrated into Unity, touching numerous relevant aspects (such as launcher, Unity panel, notification and Messaging Menu), aspects backed by the how-to step-by-step code.
Hello Unity is a demonstrative example-based tool that aims at delivering a properly organized learning process on how to integrate an application into Unity shell.
Hello Unity 2.0 has been released, adding new sections (Message Menu and Notifications) backed by related "live" examples.
The code is now displayed with highlighted syntax, approach helped by numerous added comments that are to improve the overall code understanding.
Unity is both a complex (as a structure and provided features) yet simple shell, in the sense that integrating an application into Unity is relatively simple.
Ubuntu developers have created a "hello world"-like application, that is to bring a helpful "light" into creating integrated applications under the Unity shell.