Brendan Enrick

Daily Software Development

Ball Flow Like Champs

I enjoy the Agile Ball Flow Game. It’s a challenge that emphasizes a lot of what agile practitioners find value. The theme of the game is that you’re working in a toy factory and you create toys by passing them around to the other workers. Each worker needs to touch the toy at least once, no two workers can touch the same toy at the same time, and you can’t pass the toy to the person next to you. As orders come in, you try to complete the orders as quickly as possible. If you mess up one of the toys (drop it), you have to start over creating the toy.

In the game, you want to keep track of when you start making each toy and when each one completes. This lets you track your lead time, cycle time, WIP, etc. From this information, the group can see what works well and what doesn’t. They can determine how to adjust their process to improve their toy-making abilities.

At the Hudson Software Craftsmanship meeting earlier this week, we performed the agile ball flow game. No one there had done it before, so it was a great opportunity to see how they would organize themselves and complete the solution. In total, we had 14 people at the start of the game.

Round 1

I started the group off with 20 multicolored balls. The hollow plastic variety commonly found in children’s ball pits. They’re easy to toss short distances, but can be tricky for a long distance toss.

They first created a circle to facilitate passing. One thing they did very right was passing 1 ball around as a demonstration so that the whole team could practice and get an idea of what they were going to be doing. Much better than just assuming that everything will work as expected!

They completed the full order of 20 in just over a minute and thirty seconds. A few of the balls dropped, but were picked up and reintegrated into the process. Their effective process worked so well, because most of the team had enough slack to not feel overwhelmed.

Round 2

In the second round, the team estimated that they would be able to complete things faster. They estimated the time to complete to be around 45 to 60 seconds.

As part of their retrospective, they realized that their pull model they were using worked effectively, but if they shifted forward and backward a little bit, they could pass more easily. This was their slight adjustment to the process.

It worked! They managed to keep more balls from falling in the second round and really improved their time! They noticed that their issue was in contentious passes around the circle, and they adjusted to account for it. Well done! They were a hair under 40 seconds, which is the fastest second round time I’ve ever seen.

Round 3

Kids these days aren’t just interested in those old-style toys, which means that the challenge needs to change a bit. They’re still fun, but the new thing is dart guns, so now the team needed to also pass around foam darts. With such a well oiled machine, could these darts present a challenge?

The darts are tricky, because one end is rubber and weighs a bit more than the other end. These were obviously more challenging to pass, and the group spent some time discussing how they would work.

The team decided to start with the darts to get the more difficult items out of the way first. At first, this seemed to work, but darts started falling. After starting most of the darts a second time, the group ended up with a time just over a minute and twenty seconds. Not bad, but quite a fall from round 2.

From the retrospective discussion, the group established that they needed to drop the darts into people’s hands. Tossing just wasn’t working well. They also decided that they should probably send multiple darts at a time since they were going to be dropping them, it should be safe to do.

Round 4

Armed with a new plan, the group decided to start the darts 5 at a time, which would mean 2 sets of darts traveling around the group.

Not surprisingly, only 3 darts of each set made the round trip. Still probably an improvement, but it might have been better to have done 2, 3, or 4 darts at a time instead. Perhaps something to try in the future.

This round was full of dropped items and ended with 1 dart making the rounds all alone. In the end WIP was just 1 for the whole group. The time wasn’t bad, but it was obvious that the group could do better. So far they hadn’t made any huge gaffs either though.

Round 5

This round was about being more careful and getting the passing in place as best they can. Perfect answer, team. They knew not to make big changes. What they were doing was working, and they were seeing improvement. A big change here would just upset things.

The group finished on a high note, being one of the more successful groups at ball flow that I’ve seen. They completed the challenge like champs. Not once did they try something crazy like shooting WIP through the roof (I’ve seen it!)

Agile tells us that we need to limit WIP and bring cycle times down. Those are the focuses of the agile ball flow game. It lets the group self organize through planning, spiking, testing, and doing retrospectives. If you want to teach a team about agile, the ball flow game is a great way to do it!

I primarily use Karl Scotland’s method of running the agile ball flow game. Make sure that you also use this spreadsheet template when running the game. It makes tracking times much easier.

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