This paper deals with Computer-Based Systems architecture components, called as application patterns, and with their employment for design reuse. The first two sections introduce the concept of application patterns, relate it to the well-known object-oriented design abstractions, and specify the appropriate terminology. Employing application patterns that demonstrate the concrete examples of reusability, the kernel of this contribution presents two case studies, which are based on real design projects. The paper focuses on identification, creation, and initial classification of reusable application patterns while retrieval, adaptation, and storage reuse tasks are only mentioned at the conclusion as a launching research.