AS 4.1.1 Q about symbols in the Project window

hello i'm trying to better understand the logical structure of android code and resources, starting with the different types of files and folders in my project. There are many different icons with various symbols and colors. In this image there are 5 different folder icons, 9 different file icons, and an elephant. I've edited and executed a few basic open-source apps, but i still don't know what those different icons mean.
thanx, mike

 

well i suspected as much. 120 views and nobody knows the answer. I can see why the developers at google don't have this info in their documentation, but it would be nice if someone could see to it.