This guy is an woodworking engineer and makes all kinds of fun stuff out of wood. He also has good explanations of what he's doing and how he did it. Website: http://woodgears.ca/machines.html
Blunt Umbrellas makes umbrellas with blunt corners, among numerous other innovative design features. By removing the pointy corners, it makes for increased safety, but it also distributes the tension of the canopy more evenly.