Artificial neural networks—systems of interconnected processors that attempt to mimic the structure of the human brain—are usually used for things like facial recognition. Feed a neural network enough photos of your own face, and soon enough, it will learn your dimples, your chin, the distance between your eyes—and be able to recognize those things the next time it sees you, just like a toddler would. But as a handful of researchers have shown recently, there’s no reason neural networks can’t also approximate the brain’s weirder and more creative processes—processes like dreaming.