Today, Saturday 7th May 2011, there were six code retreats around the world! They were in Belgium, Spain, UK, USA, and two in Romania! We all did the same challenge: implementing Conway’s Game of Life in pairs, using test-driven development, in iterations of 45 minutes, discarding code at the end of every iteration and pairing with somebody different for the next iteration. We introduced a few extra challenges in every session! ;)
I co-facilitated the code retreat at Sheffield University. We had 18 participants: a good mix of computer science students, professional programmers, people who code for fun, and someone who seemed to have been dragged along but got thoroughly stuck into solving the problem along with everyone else! :)
In iteration 1 we gave everyone chance to explore the problem without heckling to see how they would do. The only special challenge was to pair with someone they didn’t know. In the retrospective we talked about the languages and classes used.
For iteration 2 we talked about TDD as in, letting the tests really drive the code in the direction they want to go. We challenged people to do the very simplest thing they could possibly do at each stage. Many people found themselves writing unnecessary code, so we kept bringing them back to the rules of the game. The retrospective brought up questions of where to start, and whether a cell should be responsible for its own state, or whether a separate entity should know where all the cells are.
In iteration 3 we encouraged people to try a different starting point, to see how that worked. We stipulated that the code could not contain any booleans, like true or false or strings or numbers representing boolean states. The third iteration was sneakily only 30 minutes long, which we didn’t tell anyone until after the retrospective! There was a good discussion about using a grid to hold the cells, versus having an array of cells who know their coordinate position.
Throughout the day, at various points, we were able to have Skype video calls with other code retreats. We found this very enjoyable: we discussed the different implementation options with other people who were also tackling the same problems. During the day, Sheffield managed to communicate with all the other code retreats: Valladolid in Spain, Cronos in Belgium, Bucharest and Timisoara in Romania, and finally, towards the end of our day, Pittsburgh in Pennsylvania, USA, just as they were at the end of their second iteration.
We also had two projectors constantly showing the twitter #coderetreat hashtag on tweetviz.com and a slideshow of pictures on hashalbum.com. These things really helped us to feel connected to a bigger community of people sharing a similar experience at the same time.
After lunch we introduced Keith Braithwaite’s TDD as if you meant it and for iteration 4 we challenged people to obey the strict structure given. The purpose of this was to really break everyone’s normal processes to avoid mental shortcuts. It really ensures that the solution is exactly what the tests require, and nothing more. It was a tough challenge but it was taken well. A lot of people found they came to a better solution when these restrictions were applied.
In iteration 5 nobody was allowed to use if statements. (Or case statements, ternary operators, etc.) We also focussed on ping pong pair programming. This is where one person writes the test, the other person writes just enough code to make it pass, then writes the next test and hands back. During the day i had seen a lot of rather uneven pairing, where one person was doing most of the work, and the other was mostly just watching and commenting. Ping pong helps to address that by bouncing back equally between the two. Comments in the retrospective were that you had to concentrate harder, and felt more engaged because of it. I was surprised that many people had not paired that way before.
Iteration 6 was the last one for us. (Unlike Valladolid who went on to 8 iterations!) We gave people a bit longer and told them to just enjoy this one. The restrictions were that no method could be more than 3 lines long, and the code you wrote had to be the best you could possibly do. You had to write something you could be totally proud of. For most people, they said their code wasn’t the best they could possibly do, but they were definitely proud of it! :)
At the end of the day we did a raffle. Entry to the raffle was by way of a donation to Bletchley Park, for which we raised £200. Names were shuffled in a Ruby array and winners received either a copy of Apprenticeship Patterns or a software craftsmanship motivational calendar.
With that done, all that was left was a trip to the pub to relax after a good day’s work! :D
Thanks and kisses
I thank Tom for being a fantastic co-facilitator, and Chris for doing an excellent job of organising everything: food, refreshments, sponsorship, venue, my hotel last night, and probably a whole lot more that went so smoothly it was unnoticed.
Thank you very much indeed to the sponsors and supporters: epiGenesys, University of Sheffield Enterprise, O’Reilly UK and The GIST Foundation. It would have not been nearly as awesome without your help.
Thanks to all the people around the world who talked to us over Skype – it was great to feel part of something so much bigger than just us.
Thank you so very much to everybody who participated today. You really made it a great day for everyone.