I'd like to see a discussion here diving more deeply into the architecture of what's happening. Are we compiling code and putting it on the Adruiono? Are we controlling it remotely from a Java process on my desktop? People reading a recipe like this don't *just* want to make a light blink, they want to get their heads around what it means to program an Arduino from Clojure. You don't have to tell them all the details of everything, but you should give them enough information to start exploring on their own. This will include things like what the messaging protocols are, what kinds of messages you can send back and forth, and what the limitations of the system are.