Graphic::Toolkit::Color 1.9 brought several big new features which I will write about when 2.0 comes out - just to sum up what changed since 1.0. This time I want to describe the internal changes, since this release completed an in-depth rewrite. So this will be about software engineering, architecture and coding style. TLDR: simple, clear, DDD, OO by composition and arg and a color space DSL!