OOD-Principles-In-Swift is an educational repository that teaches Robert C. Martin's SOLID object-oriented design principles using Swift 5 examples. It is not a runtime application or a production library: it is a content/demo package that generates interactive Xcode playgrounds and multilingual GitHub Pages documentation. The canonical code lives in source/SOLID/*.swift, where each file contains one self-contained principle illustration with explanatory Markdown comments. Bash scripts named generate-playground-*.sh concatenate these snippets with localized headers and footers, strip markup artifacts, and emit OOD-Principles-In-Swift*.playground/contents.swift plus README-*.md for a dozen languages. When consumed, the primary entry point is OOD-Principles-In-Swift.playground/contents.swift, which renders five SOLID sections in Xcode's playground UI. The repo also acts as a Jekyll site via _config.yml and _layouts/default.html, hosting the translated READMEs on GitHub Pages. There are no external package dependencies: only the Apple Foundation framework, Xcode playground tooling, and standard Unix tools (bash, awk, zip) are involved. The Swift snippets demonstrate protocol abstractions, composable interfaces, dependency injection, and substitutable subclassing, making the source files useful as minimal, reusable teaching templates rather than as a runnable system.