Your circulatory system is a fractal for similar reasons that trees are fractals for similar reasons that watersheds are fractals.
Fractal structures are probably the rule rather than the exception for basic reasons of space and energy efficiency.
Here's another interesting fractal thought, where is the universe? In your head, or outside of it, or both?
So the neuronal structure representing the universe in your head is at least in some ways similar to the objective outside universe, if there is such a thing, and if there is such a thing then that neuronal structure in your head is also in(and of) that objective universe while also being similar to it.
A good term for fractals is self-similar.
Self-similarity all the way down.
I am a strange loop. - Douglas Hofstadter
It's in you, and you're in it. - Alan Watts
That which is below is like that which is above & that which is above is like that which is below. - The Emerald Tablet
https://en.wikipedia.org/wiki/Emerald_Tablet#Newton.27s_tran...
If you consider the Curry-Howard correspondence in connection with Gödel's Incompleteness Theorems, the fractal nature of the universe seems inevitable.
On the other hand, at very large scales the universe is expressly homogenous (smooth) https://www.space.com/17234-universe-fractal-large-scale-the...
W/r to larger and more wide-ranging questions, e.g. if the mutli-verse has some sort of deep fractal meta-structure, and/or the recursion of fundamental quantum computing operations, the jury is still entirely out.
I assume that's because of looking at it through low pass filters, inadvertantly.
Also this, and the article it was saved from, bringing music and the proportions of the human body into the equation: https://www.pinterest.com/pin/358317714073877302/
Finally this: "Every society has seen architecture as something that transcends its functional role, as a diagram of the cosmos,"
https://www.theguardian.com/artanddesign/architecture-design...
Edit: I'm an architecture historian so I didn't mean it if I came across as pompous -- but that Gelernter link conveys a weird sense of CS being superior to the art historians, and at the same time makes more of recursive patterns in physical architecture than is justified. I have mixed feeling about this projection of the ideas of one field on to another: something like the Sierpinski gasket is not good architecture, and it takes a real expert in building to understand the difference, not a mathematician/computer scientist who can spot recursion. So my possibly contentious point was that a schematic reading of architecture as recursive (or even cosmic) is valid but also kind of the most superficial non-aesthetic form of thinking about architecture...
http://www.unz.com/isteve/nyt-finally-confirms-barcelona-ter...
https://www.facebook.com/238044912896496/videos/163973293272...
Just to be clear, this knowledge wasn't lost accidentally. It's part of what was contained in the books and manuscripts destroyed intentionally by colonizers.
https://www.amazon.com/Indras-Pearls-Vision-Felix-Klein/dp/1...
http://www.surya-world.org/hindu-temple-and-the-structure-of...
If that is so, that the universe has a high degree of complexity at every scale, is that really controversial?
Here is an excellent 20 min introduction to fractals: https://www.youtube.com/watch?v=gB9n2gHsHN4
[1]: https://www.youtube.com/watch?v=tsuYZg8k-Zc [2]: https://www.youtube.com/watch?v=00gAbgBu8R4
