So, why do you think circles appear so natural to humans? Just off the top of my head I can spout off several examples in history/evolution where the circle was the chosen symbol or tool…The Wheel, council circles, board room tables [most], symbol for Zen, shape of countless celestial entities, zero, full, empty, geometry ad infinitum! This might venture into the realm of a great debate but if not - what do you think, why are circular entities [shapes, tools, symbols] so universally known and used throughout history and civilization?
Shape of the sun?
With a wheel on an axle, the more it deviates from being a circle, the bumpier your ride will be, so a circle is clearly the best shape for a wheel.
Good symbol for anything you wish to imply has no begining and no ending? Implies no hierarchy?
That’s kind of cool. But what does that mean for growth? Does growth simply happen in some circular pattern?
Physically/geometrically, circles and spheres offer a minimum surface to volume ratio. Also, a circle or cylinder is the natural result of anything rotating around a fixed center point such an axle, compass, or lathe. It would be pretty hard to avoid them.
Impossible to avoid them, they are almost perfectly essential.
So in physics, this makes them tend to happen naturally wherever a volume of deformable material is constrained by something that pulls it together - be it a mass of incandescent gas pulled together by gravity (a star), or a volume of air pulled together by the tension of a soap bubble’s skin.
In nature, the same payoff makes them selectable - with seeds, for example - a plant can pack the maximum volume of endosperm into the least costly container. That isn’t the only criterion acting on the selection of seed shapes, though - which is why not all seeds are spherical.
And, circles are as symmteric as you can get (for a plane figure).
Boobies.
Our life is an appenticeship to the truth that around every circle another can be drawn; that there is no end in nature, but every end is a beginning, and under every deep a lower deep opens…Emerson 
The spherical ones aren’t usually natural.
This post reminded me of a Reuleaux triangle. Nifty, although it doesn’t make a good wheel.
No, but to an infant, the mother’s breasts probably do appear more or less spherical.
Everyone needs water, so water is where people settled. Droplets usually end up round, and ripples in water are concentric circles. What always fascinated me was what makes a right angle so special that we can recognize it immediately?
Experience since childhood. Primitive people raised in cultures without so many right angles are slower to notice them, but faster to notice everything else.
Growth is a result of hard work. Hard work is often accomplished with the aid of wheeled devices (like a flour mill–which is a very old invention.) Circle = Productivity = Growth
That beautiful.
That’s very fundamental.
I’m a bit surprised everyone is making this so complicated.
A circle is the easiest shape to create.
This is not so much an understanding of a simple circle, but a temporal spiral. I think the spiral model is what yer seeking. Nature does that very well.