We met for a 3 day HI fest on one of the Dutch islands (Vlieland), including workshops, poster presentations, an introduction to the new structure of HI, a HI movie night, and of course hiking, biking and board games. Matt Johnson from IHMC in Florida presented as in invited on on “Co-activity analysis” and guided the subsequent exercise to try and make a co-activity analysis for our two Case Studies on Diabetes and Robotic Surgery.