Not sure I understand the distinction -- is that meant to be clearer?
"Choice of layout": What is that referring to? It's not the "division of code into subroutines", as that's mentioned later on as being off-topic (EDIT: this is explained in the next section, but it could perhaps be briefly clarified on this page too)
the link to the notebook at the beginning gives an error.
Typo: rigourous should be rigorous