This example demonstrates two things:
In this example List is not a module with the typical module exports (init,
update, view and Actions) it is instead a function that creates an object
with these properties. The function takes another module and returns a list that
contains items of that module.
List only makes an assumption on how its content should be initialized but is
otherwise completly agnostic of what is contains. This is example shows how it
completely unmodified can contain the Counter module from the counter example
as well as a new Switch component.
This application demonstates a three level nesting. The top level handles tabs of lists of counters/switches. Notice how the top level is completely unaware about whether or not the content of the tabs contains nesting as well.
Each level is only concerned with any levels directly beneath it and not at all concerned with levels above it. This ensures that additional nesting can be added to a module without affecting it's parent and that a module can be nested deeply inside other modules without it having any knowledge about it.
The above should ensure that nesting to arbitrary levels is completely straightforward without the routing of actions getting out of control.