This bell would be illegal in Denmark, where our laws clearly state that you are only allowed one signal giving device and that any signal giving devices attached to vehicles (including bikes) can only produce one constant sound.
I wrote both my master thesis and PhD on Hoare's Communicating Sequential Processes. I really enjoyed it's simplicity, expandability, and was always amazed that it inspired and influenced language constructs in Go, Erlang, occam and the likes.
How this would be enforced is a different topic.