Emergence of complex patterns

I think it is amazing how in the universe we see diverse and beautiful patterns and structures. Even relatively simple systems can self-organise to produce things one would not expect or predict. Consider clouds, turbulent flows, leopard spots, a tree leaf, spiral galaxies, biological cells...
It is also amazing and beautiful that we can develop relatively simple mathematical models that can produce similar patterns.
This is emergence!

Here is a beautiful example that recently came to my attention.

The associated PRL is

Faraday-Wave Contact-Line Shear Gradient Induces Streaming and Tracer Self-Organization: From Vortical to Hedgehoglike Patterns

Héctor Alarcón, Matías Herrera-Muñoz, Nicolas Périnet, Nicolás Mujica, Pablo Gutiérrez, and Leonardo Gordillo

There is also a Physics story too.

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