Perfection is overrated—at least when it comes to complex systems like the power grid, food webs and advanced materials. For decades, scientists generally assumed that networks function most reliably when their individual components are as similar as possible. But real-world networks are rarely uniform.

Artificial intelligence programs used to classify images could be trained much more cheaply using a surprisingly simple method inspired by the childhood game of 20 Questions, according to new research posted to the arXiv preprint server by a team from the University of Bristol.