In the week 3 README, client/server is described as an application of "Separation of Concerns" (SoC) which does not seem entirely correct to me. Splitting into a client and a server is a practical necessity whereas SoC is more a design choice. SoC is of course relevant in how you would structure the client and the server individually.
This is certainly a nit-pick and I do appreciate introducing concepts such as SoC, but I am not sure this is the right way.