The complexity of world events can’t be modelled by a flow chart or even the most sophisticated algorithms. Instead, military officers, diplomats, and policy analysts sometimes turn to an old but sophisticated set of tools: war games. Simon Parkin observed officials playing one in order to predict and contain a potential geopolitical conflict. And Michael Schulman speaks with Pam Grier, the pioneering star of blaxploitation films like “Coffy” and “Foxy Brown,” about her singular career in Hollywood.