* Further simplify `Box` diagrams
I think we can improve the drawing by simplifying them and making them
more symbolic. Followup to #374.
* Apply suggestions from code review
* Update box-recursive.md
Adding Speaker Notes. This is a high-level guideline what to say, so we can settle on one explanation and review it.
This may be very obvious with the background in some languages, but be very non-obvious in languages that always
use references and never embed structs into structs.
* Fix wording
Co-authored-by: Andrew Walbran <qwandor@google.com>
