In the Hernesaari Master Plan project (2006-2007), Arkki pupils participated in an idea competition for the Hernesaari master plan. The competition, organized by the Helsinki City Planning Department, aimed not to find a winner but to stimulate discussion and gather ideas from citizens. The competition also involved three architectural consultants and two citizen groups.

Initially, Arkki pupils visited Hernesaari and explored the area through a multi-sensory approach. Participants created sensory maps of Hernesaari: smell map, sound map, texture map, structure map, material map, green map, shape map, color map, and even maps from the perspectives of a frog, bird, and explorer.

Design work was done in various ways across age groups: the youngest pupils drew, painted, and built models of Hernesaari, creating fictional stories about the area’s history and people; basic education groups worked on designs based on the competition brief; advanced groups reviewed younger students’ plans and created an overview of the main themes from different proposals. Ultimately, a shared plan was created and a model was built.

Arkki pupils presented their plans, allowing the general public to ask questions and provide feedback. The pupils’ plans also received media attention. As late as 2012, Arkki pupils had the opportunity to review city plans at the Helsinki City Planning Department, which had utilized the idea competition and ensuing discussions in its planning.