The fourth assignment for my Prototyping lab (Fall 2012) consisted of the iterative design for a microwave console. The microwave UI had to include certain features and buttons in each iteration. After each version, we ran Heuristic Evaluations with our peers, and collect Usability Aspect Reports (UARs) from each one. There were two versions made in paper, and two versions made using the Flex programming language.
What I learned: Thanks to iteration, I discovered errors that I otherwise would never have seen, and my design became stronger with each pass. This assignment, more than anything else in the class, proved to me that designs need time to grow and develop before they are ready to be publicized. I also learned that it often requires very complex back-end code to produce the simplest things (i.e. the microwave countdown timer).
Attached is a sample paper prototype, a UAR, and the final working prototype.
A word of warning: the alarm on the final version is loud and lasts for a long time.