: Presented is a paradigm of how a design concept can be converted into a system of production rules to generate designs. The rules are expressed by the means of shape grammar formalism. The paradigm demonstrates how porosity a concept transferred from biology, medicine and organic chemistry was implemented by architect Steven Holl and his team in designing the 350-unit student residence Simmons Hall at MIT. In the presentation, spatial algebras, rule schemata and shape rules are used to capture Holl’s version of porosity.