Williams also wants to eat into the CPU. He says that many processes requiring fuzzy logic, like recognizing a face, are very hard to work out with that yes/no logic of a digital computer. But for an analog computer—like, say, the brain—it's a piece of cake. So Williams proposes a CPU with multiple processing cores: Some digital for the number crunching that today's computers do so well, and others using analog memristors. Take facial recognition. Someone's face can change from day to day, and definitely from year to year. But it's not a drastic change that a yes/no digital system is good at figuring out. It's a mild difference with some degree of change along a continuum that Williams says is perfect for an analog computer.