In June 2024, the OPUSH Delft team engaged with public libraries’ “DOK designers”, a group of children aged between 7-12 years old to take part in the Citizen Science pilot “Check je plek”. There, the participants were invited to share from their experiences what is their favourite place in Delft, and what make this place unique and important to them. Having identified urban design elements a discussion was further developed about urban sustainability and life in the city. The pilot was followed with a second investigation of the interior design of the library itself and the participants’ own ideas about how the space of the library could look like and be re-arranged in order to facilitate study and play. The growing discussion and decisions of the group was aimed to the creation of a collective design for the public library.