The challenge itself was an agent-based model with rewards, i.e., it was closely connected to partially-observable Markov decision processes and game theory. In my solution, (which earned me an honorable mention) I took neither approach but just played around a bit with strategies I chose ad hoc. Despite this, I was amazed by the rich diversity of behavior I observed. It took me some 40 work hours but it was totally worth the effort. Thanks heaps to the organizers of the challenge, and congrats to the winners -- I hope I get the chance to participate again at some later time!