Even though this is five years old, I hadn’t seen it before. It’s a very cute trick. The followup by Josh Millard is even better: http://www.joshmillard.com/2007/10/04/retro-histo-making-an-...

It's a good thing he created (and you posted) that followup, because otherwise I would've spent the rest of my morning implementing the same idea.

Relevant: http://xkcd.com/688/