Even though I typically avoid building interactive diagrams, sometimes they are the only way to convey the point. This blog post by Amit is a great example. You can interactively explore the relationship between the driver’s head position, the three car mirrors, and the resulting blind spots.
http://amitp.blogspot.com/2011/08/interactive-diagrams.html
Here is a screenshot of the app, click to go directly to the interactive diagram
