The teaching of programming concepts and algorithms very much depends on the mental models developed by scholars when learning how to program. There is a rich body of research on how to best teach programming. Nevertheless, many instructors follow a presentation-based approach where existing slideware such as PowerPoint or Keynote is used to show a sequential series of slides with static pieces of source code. Such a presentation-based approach based on existing slideware tools might not be optimal for the authoring as well as the delivery of programming courses. We outline how presentation-based eduction in programming can be improved by paying attention to existing research on how to best teach programming. We derive a number of requirements for more efficient source code visualisation in presentation tools and present an architecture as well as an extensible prototype for enhanced presentation-based teaching of programming. The presented interactive source code visualisation plug-in for the MindXpres presentation tool can be seen as a step towards enhancing existing slideware in order to achieve a more efficient and interactive teaching of programming concepts and algorithms. The ultimate goal of the presented approach is to present source code in a way that reinforces a user's mental model and thereby increases the knowledge transfer of presentations delivered in programming courses.