Despite rapid advances, modeling a variety of instructional designs to support variations in teaching and learning during the design of educational technologies is still an open challenge. In this paper, we propose a patterns based approach for the design of educational technologies to address this challenge. This is in contrast with existing literature that focuses either on patterns in education or in software, and not both. The core idea of our approach is to leverage patterns for modeling instructional design knowledge and to connect it with patterns in software architecture. We discuss different categories of patterns in instructional design. We then present the notion of "Pattern-Oriented Instructional Design" (POID) as a way to model instructional design as a connection of patterns ("ProcessPattern, ContentPattern") and integrate it with "Pattern-Oriented Software Architecture" (POSA) based on fundamental principles in software engineering. We demonstrate our approach through adult literacy case study (287 million learners, 22 Indian Languages and a variety of instructional designs). The results of our approach (both web and mobile versions) are available at http://rice.iiit.ac.in and were transferred to "National Literacy Mission Authority of Government of India: for further proliferation.