I find the "app structure" schematic (http://developer.android.com/design/patterns/app-structure.html http://developer.android.com/design/patterns/app-structure

I find the "app structure" schematic (http://developer.android.com/design/patterns/app-structure.html http://developer.android.com/design/patterns/app-structure.h...) a very useful visualization to see the screens of an app in one glance. Any ideas how they made this schematic?