I hate to be "that dick" so let me first say that this is damn impressive stuff; kudos to the authors for some serious CSS wizardry!
It's also completely and totally useless. The person / people who did this are obviously talented and have a lot of expertise. I'd really rather see people with this level of ability contributing meaningful, useful tools / techniques to the community rather than seeing this type of post over and over again.
I can hear the arguments now, "but it shows off the power of CSS!"
No, it doesn't. It shows off what a clever person can achieve by tinkering with a system; but there's no practical value to most of the techniques demonstrated. CSS has a lot of power; but its best demonstrated by projects like the CSS Zen Garden that show off real-world CSS use.