[Grustaf]

Quaternions are beautiful and natural, not weird, but I'm always happy when they get some attention! This was a very interesting article, thanks. It does seem to confuse quaternions in general with (unit) quaternions as used for rotating vectors. For example:

>So don’t think of quaternions as a 4 dimensional hypersphere of radius 1

This is also a bit weird:

>But nobody would ever suggest that we should think of a rotation matrix as a 9 dimensional hyper-cube with rounded edges of radius 3.

Even weirder when they claim that the axis-angle interpretation of (unit) quaternions "breaks down".

Anyway, back in high-school when I first became fascinated with quaternions I certainly didn't expect to be working with them on a daily basis two decades later. The moral of this is that anything you learn can become crucial to your career...