I've been participating in the Lisp Game Jam for several years now, and the next one is starting on 10/28, and with each attempt I've been accumulating code that forms something resembling a game engine. I'm now attempting to solidify some of the concepts I've been exploring in order to make a game engine worthy of releasing in case someone else wanted to use it, too. I've named this engine Catbird, continuing the bird theme established by my game programming library, Chickadee, which the engine is built on.