A successfully engineered physical system will reach a state of complexity such that it needs its own vocabulary and semantics for proper comprehension. Among many other things, I have designed a three-tier control system for an autonomous submarine, a language for a tabletop quantum computer, and two proposed experiments in neuroengineering: a neural prosthesis that would program a fly's natural avionics, and a 'microbrain' comprising 1,000 cultured neurons that could perform a sophisticated behavioral task.