Mattias Velamsson recently shared a beginner's tutorial for making a GUI
(Graphical User Interface) in Ruby titled "Ruby GUI with Glimmer". It
provides a step-by-step code walkthrough that produces a full-fledged
web-API-driven table-based business application. It uses various gems and
APIs like glimmer-dsl-libui, dotenv, Net::HTTP, URI, JSON, and the
Exchange Rates Data API.