A fair question. An easy answer is that I thought Lisp was pretty cool, and that the students were capable of it. And, pragmatically, I was experienced with it,

A fair question. An easy answer is that I thought Lisp was pretty cool, and that the students were capable of it. And, pragmatically, I was experienced with it, unlike MaxMSP or Processing. But there was something philosophical: I liked the idea of introducing them to the feel of fundamental computer science, rather than a nice layer over computers for artists. (And what artists actually use those nice layers?) I wanted them to experience an open source ecosystem (unlike Max), and I felt that the Java-base of Procesing was off aesthetically -- too many layers over the machine. Thinking about the OP, I do wonder what it would have been like to teach coding-for-artists with Hypercard. One thing I love about Emacs Lisp is that it is only grudgingly visual. That it returns computers to something which sends output to a TTY. It gives people who have grown up with a GUI a vision of what computers were like before. I like that Emacs (and Lisp) are things with a history and touch on earlier eras of computer culture.