Hah this is awesome. Not only from a coding perspective, but from one artist to another - congrats. I really enjoyed that comic about Lisp fleet. Comic also exposes one nasty thing about it - there is no single implementation that has all of the fleet's features. Do you recommend some specific implementation to go with your book? Anyways, first check that comes in November and I'm buying. Congrats on your project once again, really looks like something special!