The goal of the four days workshop during the Smart Geometry conference was to design a constructive system composed out of uniquely formed Styrofoam blocks. The architectural potential of the developed system was tested through applying it on the design and fabrication in a 1:1 scale prototypical building structure. The participants were challenged to analyze and test different interlocking systems by making simple prototypes in order to apply the outcome to an overall system. The prototypes were fabricated using a robot in combination with a hot wire cutting machine. Existing constraints set by the fabrication process hat do be considered as well as to check stability and flow of forces. Gaining stability due to friction and interlocking system were seen as the potential of the fabrication process and had to be exploited as far as possible.