Really nice explanation and code samples. I'm glad to see more accessible materials emerge for explaining what signals are. The Elm website already does a good job, but I think the extra detail in this article will help more people grok it.

I have done my own exploration in this area. I hack on a game engine written in Scheme that includes a signal implementation, a declarative scene graph, and a live coding environment via a REPL server. It's not as glamorous as Elm, but I'm quite proud of it and I plan to make the first release soon.

http://dthompson.us/pages/software/sly.html

An older blog post I did with code samples and a quick screencast when the project had a different name:

http://dthompson.us/functional-reactive-programming-in-schem...