In the above video, Clayton Boyer shows how oddly-shaped gears can function smoothly. Okay, the square gears shouldn't be a surprise. But then he moves on to ovals, then fish, and then things that look like Rorschach inkblots.
via Gizmodo | Official Website
Previously by Clayton Boyer: Create Your Own Amazing Wooden Clock
I'm even more in awe now that I know how to make the weird gears.