The OS (OpenStructures) project explores the possibility of a modular construction model where everyone designs for everyone on the basis of one shared modular geometrical grid, a common open standard that stimulates the exchange of parts, components, experiences and ideas and aspires to build things together. The ultimate goal is to initiate a universal, collaborative puzzle that allows the broadest range of people – from craftsmen to multinationals – to design, build and exchange the broadest range of modular components, resulting in a more flexible and scalable built environment. An open modular system of this kind has the potential to generate flexible and dynamic puzzle structures rather than uniform modular entities, introduce variety within modularity, stimulate re-use cycles of various parts and components, and enable collaborative (and thus exponential) innovation within hardware construction.