Earlier quoted context omitted.
Pinning is about positioning variables, not graph structure.
A scene graph is a scene graph is a scene graph. Whatever you call it. Also, it looks like the pinwheel demo has an error. I suggest you add one of the more advanced demos along with source code on the intro page. Just looking at the first few demos I felt it reimplemented stuff that's already possible with CSS, but it looks like it's capable of much more (the last few demos)
The game O! is open source. Everything is almost possible with HTML/CSS too, the point is performance across different devices.
Thanks, found and corrected the error.