I'm really glad to see more folks discussing Celluloid and actor-model based concurrency in Ruby, too!

If you liked this article, you may also enjoy "A gentle introduction to actor-based concurrency"(*), which shows how to solve the dining philosopher's problem using Ruby threading primitives, celluloid, and a made-from-scratch actor model similar to what is shown in this article:

https://practicingruby.com/articles/shared/plgjjonrkggl

Disclaimer: I am the editor for practicingruby.com, and this is one of our contributed articles (from Alberto Fernandez-Capel).