I always have so much fun at Agile 20XX conferences that it sometimes feels anticlimactic when they end. This year, however, I was lucky enough to get one of the last few tickets for Corey Haines’ latest CodeRetreat in Orlando.

The CodeRetreats are focused on having fun while learning, and follow a simple formula: 45 minute sessions of pair-programming on Conway’s Game of Life, then deleting all the code written and taking a 15 minute break. As well as giving up his time, Corey organises a storming lunch. Thank you Corey!

Deleting the code, for me, is the magic. I didn’t fully understand until Corey tutored me out of my outside-in, BDD habit at the last Code Retreat in Bletchley Park. “Why did you start with the Grid?” he asked.

“Well… because that’s how I’ll know I’ve solved the problem.”

“Are you trying to get things done?” Corey asked. “Don’t try and get anything done. 45 minutes isn’t long enough, and we’re going to delete the code anyway. Why not pick something interesting and see if you can find a different way to do it? Why not look at the rules, or a single cell, or the number of neighbours?”

I got it. CodeRetreat isn’t about solving a problem or getting something done. It’s explicitly the opposite. It’s about learning, even if that means you never solve anything or get anything done. The 45 minute period is just long enough to learn significantly but not quite long enough to make any real headway, unless you already know the Game of Life backwards.

As part of teaching BDD and driving out various BDD tools, I’ve produced multiple implementations of the Game of Life in Java and C#, to the extent where I already have a good idea of the classes I’m going to use. That can actually be a handicap in the CodeRetreat, because it makes it hard to learn anything new. I often find myself letting my pair take the direction, just to see if any other interesting patterns emerge.

In Orlando, we were lucky enough to have several great programmers amongst us – including Michael Feathers, Brian Marick and Uncle Bob. Having already experienced a cage match between Michael’s Haskell and Brian’s Clojure implementations of the Game of Life, I was excited by the opportunities to learn a new language. Brian was kind enough to show me some of the language features in Clojure. We didn’t really get very far with the problem, but that’s OK – the object was not to solve the problem, just to learn. Thank you Brian!

For the last session of the day, we voted to use a bit of extra time to conduct a longer session, and Bob kindly volunteered to help me continue exploring Clojure. We started with a function which would find all the potential candidates for life in the next generation, and worked from there.

10 minutes before the end of the session, we had a working copy, which Uncle Bob has kindly blogged here. The code is a little tidier and a lot more readable than the version we ended up with. I need to find out what conj and % do! We should also have deleted it, but since we had already gotten something done, it was too late.

Clojure turns out to be a very beautiful language, and Uncle Bob is a lot less scary in real life wonderfully patient mentor. Thank you, Bob!