Interestingly in this case, the limiter is the number of gear teeth - when down to two, stop. It's a fractal if you start your first gear with an infinite number of teeth. That being problematic, when down to 2 teeth scale back up to resume filling space with the largest gear possible ... making the real trick determining whether a gear should be placed such that it does not immobilize the chain.

I do not get it either.

Gears by themselves are just gears and those gears barely form a fractal structure, though once there was something a little bit resembling third/fourth iteration of a Sierpinski triangle[0].

[0] https://en.wikipedia.org/wiki/Sierpinski_triangle

The page itself is really cool, and I love the effect. I wonder if I would be able to use screenshots from it for personal projects? I assume not.

As the most minor point that could possibly be made – never seen · before, seems like it could be quite useful.