This report describes an experiment carried out at ParcPlace-Digitalk which sought to increase the look-and-feel compliance of portable applications built using the company's Smalltalk-based VisualWorks product. We outline the structure of the current VisualWorks user interface framework, and the precise requirements which the experimental system sought to fulfill. We go on to show how we were able to reuse design patterns from the literature in a generative fashion, to direct the evolution of the new framework. This contrasts with most pattern-related work to date, which has concentrated on discerning design patterns in existing systems. Finally, we draw generalizations from our experience concerning the evolution of software architecture using patterns. 1.