This is about playing musical chairs. At the beginning of the hackathon everybody with an idea goes on stage and presents (sometimes with powerpoint) their idea for three minutes. And they would say, ”I want to make a public finance report website. I would need two coders, one designer, and one storyteller for this task.” Usually there are about 20 projects for each hackathon, many of them new projects that people have never heard before. Then we play musical chairs. With stickers, one can see at one glance that this corner of open space already has their staffing of engineers, so other engineers go to some other groups. So people introduce themselves and just join whatever projects they find interesting that still have vacancies.