Over sushi this evening, Tom mentioned “Chua’s circuit”, or “Chua’s oscillator”. I knew that I had seen this somewhere before, but failed to remember that Chua was also the guy who first theorized about the memrister: a circuit element whose resistance is proportional to the sum of the charges that has been passed through it. Chua first imagined this circuit back in 1983, and it is probably one of the most well studied and well understood chaotic circuits ever proposed. It’s also quite simple. The page linked here should a simple circuit, with just a single op amp and a handful of other discrete components. I’ll ponder it some more: