We're still chasing that elusive stable project state where we're mostly done with large changes,

yet we keep finding more and more to tweak and improve. Besides the usual batch of corrections and

small improvements, for this change we plodded through the complete code progression for both books

one and two (_In One Weekend_ and _The Next Week_). This caught a _lot_ of issues (to our dismay),

and allowed us to generate a complete set of new render images for both books, to catch up with all

of the changes we've been making. The end result is that readers should find a significantly better

agreement between the book and their code as they progress, and their renders should also generally

match.

Besides the new rendered images, we also much improved the image parameters, which were frequently

missing from the previous version, leaving readers to guess at their values, or go to the code to

try to figure out how we created some of the images. In general, our working renders are now 400

pixels wide, usually 16:9 aspect ratio. We now use an explicit aspect ratio and deduce the image

height and other camera values, so you can tweak your render size just by changing the image width

(instead of updating a bunch of dependent parameters).

One interesting late change we made was adding explicit C++ `override` labels to subclass methods.

We did this mostly to aid code readers, but were surprised to find that it actually caught a pretty

significant bug hiding in our code (see entry in common changes below).

You'll also see a new citation section at the end of the books, to encourage uniform citations out

in the world, making it easier for people to refer to and track these books.

As is typical, though we roughly follow [semantic versioning](https://semver.org/), we're

considering this release a minor change instead of a major one. It's a common reflex, because people

generally have a (misguided) aversion to bumping the major version a lot. We consider it minor

because most of the changes are quite local, some classes get new constructors and any variances

should be quite simple and easy to fix up. Still, one might consider this more properly a major

version bump.

For our next larger-than-patch release, we're beginning a large revisit of book 3,

_Ray Tracing: The Rest of Your Life_. There's a lot of work to do, and this will likely be a

significant change and improvement. We're hoping that changes to books one and two will be small,

but that's never worked out for us before. Ah, dreams.