- The first green bar on the left is the highest. At this point the students hadn't realized what the aim of the game was - to control the average time to green. Everyone was busy beavering away on what they incorrectly thought they were being judged on - the trivial exercise of stripping backslash newline characters from a buffer. A couple of laptops would probably have carried on into the night without some gentle prompting. The height of the bar represents the average time to green remember. There were four very high individual times and the standard deviation was a hefty 174 (seconds).
- The second green bar is marginally lower, indicating the average time to green had reduced slightly. Remember that before each iteration everyone swapped pairs (and moved to a new laptop). The pair swapping was the primary mechanism by which strategies for controlling the average time to green were passed on. At this point only one swap had taken place so not much strategy passing on had occured. There were three very high individual times and an even heftier standard deviation of 196.
- The third green bar shows a bigger drop. Since there had now been two pair swaps the effect of passing on strategies was now more marked. Only now was the group really starting to realize what the true aim of the game was. They were starting to experience first hand how effective simply strategies like frequent compilation can be. There were two high individual times and the standard deviation was now down to 142.
- By the fourth iteration three pair swaps had taken place and all the groups now genuinely understood the aim of the game (which was not to produce the world's greatest unsplice function!) Every single group got to green within 8 seconds. It was noticeable that on this iteration, as soon as the bell was rung each group chose to get to and stay at green at their first possible opportunity. The standard deviation was only 22.
- The fifth iteration bar is perhaps the most interesting of all. By this time everyone understood the aim of the game and everyone was able to get their laptop to green within a very short time of the bell ringing. However, with some gentle prodding we suggested that they didn't have to stay at green at their first opportunity. Consequently, they were starting to decide whether to stay at green or continue for a little longer. They were starting to think about all the pairs not just their pair. This was the first real point when they were in control of the development process and not vice-versa. The standard deviation was 71.
- For the sixth iteration we suggested the group aim for an average time to green of 60 seconds (they were at 130 seconds for the fifth iteration). On the seventh iteration the average was 85 seconds with a standard deviation of 74. Pretty impressive.
At the end of the game people were really starting to act with more team awareness. On the first iteration none of the green pairs offered to help a red pair - they just sat watching. In contrast by the end (with a little prompting) some green pairs were offering help to a red pair.
Something else that was noticeable too: at the first iteration everyone looked quite tense but by the end they all realized it really was a game and they all looked at lot more relaxed. Their manager Lars commented on how marked this difference was.
In a review the next day one of the developers commented "suddenly baby steps were being encouraged and large steps were being frowned upon." One developer recounted instinctively firing up the debugger, only to be persuaded by their partner that there were other more effective strategies.