XP War

Extreme Programming trainer Joshua Kerievsky invents another card game.

By Alexandra Weber Morales
November 20, 2002

"The cards are really big in Europe. People buy lots of them. Before we had them made, we had a version on our site that you could print out and cut out yourself. People would actually do that and even laminate each one," said Joshua Kerievsky, Berkeley-based inventor of various educational games.

After a long day of conference sessions and expo floor crawling, what better than to sit down with some buddies, have a beer and play cards? Well, I don't drink beer and I've never learned the rules of anything more complex than gin rummy, but that didn't stop me from joining the guys at one of three tables of players in Tuesday night's Birds of a Feather gathering at SD East 2002 in Boston. Extreme Programming playing cards are the latest addition to Joshua Kerievsky's bag of tricks. President of Industrial Logic, a San Francisco Bay Area-based software consultancy, Kerievsky uses the XP cards and design patterns cards, along with other games of his own invention, to teach the practices, values and concepts behind XP and object-oriented programming. Each XP deck contains 44 problem cards, 48 solution cards, eight value cards and one joker. Rules for playing the educational game can be found at www.industriallogic.com/games.

	Developers contemplate who's got a winning hand while playing the XP Explanations game. Problem cards are red, solutions are blue.

The Tuesday-night card sharks had their choice of two games: a fast-paced version of the classic War game and a slower Explanations game. In XP War, two players each hold half the deck, each simultaneously whips out a card and the player who holds the more powerful card keeps both—the player who collects the most cards wins. The longer, more complex Explanations game requires that one or more problem cards be set in the center of the table. Several teams vie to match the best solution or value in their hand to that problem. Group consensus determines whether the solution passes muster.

In truth, neither game is fast-paced, and there often aren't clear-cut reasons why one card might trump another. Problems such as "Stories are too complicated," "Programmers don't rotate off specialty tasks" "Code is bloated and fragile" and "Coach solves hardest technical tasks," could potentially be counteracted with such solutions as "You aren't going to need it," "Continuous Learning," "Test-driven development" and "Pair program and change pairs frequently." The four values, too, have a role: Courage, communication, feedback and simplicity can solve many problems on their own, according to Kerievsky. Players enjoyed spinning tales about the problems they placed on the table—many from real life—and debating whether a proposed solution really worked. All were well-versed in Extreme Programming concepts, and many had practiced XP in their own environments. At last year's SD East conference, Kerievsky introduced Design Patterns poker, a more complex game that required an above-average knowledge of OO software engineering. Looks like he has another winner.