When designing residential buildings, the current method is to provide high-quality prototypes that can satisfy most, let’s say 80%, demands of people’s daily needs. It used to work well; however, with the explosive development in every aspect of our society, people are now not satisfied with the standard ‘80% satisfied’ design. Unfortunately, it is impossible for architects to do customized design for everyone. In this case, mass customization in housing design must be realized in an affordable way, which is customized combination of standard parts. To realize that, we have to create a logic loop dealing with the relationship between part and whole so as to enable the automation in the design. The floor plans in the building are formed by different demands. The assembly of different housing units is based on the relationship among the households living on the same floor or adjacent floors. Therefore, the unique form and different kinds of public space will be automatically formed as well. And, since each module can be replaced, users can easily change their living space if they have different demands in their lives. That makes the building keep changing and updating itself.