When we think about games, we usually imagine two or more players combating one another in a “zero-sum” situation. Whoever doesn’t win must lose, and no one’s interests coincide with anyone else’s. This is the classic, prototypical structure of a game or sport. Checkers, backgammon, gin, tennis and golf all divide fixed amounts of glory, points or money among competitors. Even in team games like bridge or baseball, the rules dictate that one side wins and the other loses.

A new form of board game is upending this convention. In “cooperative games,” all of the players work together to achieve a common objective. If they succeed, they all win; if they fail, they all lose. They are playing against the game itself.

Perhaps the most successful cooperative game is Pandemic, designed by Matt Leacock and published in 2007. Pandemic was originally marketed to serious gamers, but it has gone mainstream. It’s now for sale at major chain stores, and several add-ons and sequels have come out.

Each player in a game of Pandemic plays the role of a public health worker, such as a medic or a researcher. The enemies they fight are four deadly diseases that spread from city to city across a world map, with each new card drawn from an “infection deck.” These cards, shuffled to appear in a random order, cause existing outbreaks to worsen and new ones to start. The different roles give each player unique abilities. Only the “quarantine specialist,” for example, can prevent an outbreak from spreading to neighboring cities, so he will often move himself to a place that is already highly infected.

If the players manage to marshal their abilities and take the right actions, they will cure all four diseases and win the game. But if too many outbreaks occur, or if the players run out of resources (such as cards that let them fly to afflicted cities), then the players lose.