This reminds me of a demo page from the late 90s that made me appreciate graphic formats on the web, where it highlighted what true alpha transparency could really accomplish and what you miss out on when you don't have it http://www.libpng.org/pub/png/pngs-img.html

Beyond just the topic at hand, this is a wonderful example of showing people how much more the web can do and why it is important that we keep pushing for progress.