It would be very convenient if the source code would be distributed into folders, where the root would contain folders with the ordinal number of the chapter. It would be much more handy to search for the desired project.
├───ch01
│ └───Foundations
│ ├───elixir
│ └───erlang
├───ch02
│ └───WritingProperties
│ ├───elixir
│ └───erlang
├───ch03
├───ch04
├───ch05
├───ch06
├───ch07
├───ch08
├───ch09
├───ch10
└───ch11