Mathematics, physics. We live in a chaotic, unpredictable universe. This is a grid of 812 double pendulums, each with slightly different initial conditions for the two angles of the pendulum. By Jonathan Nafziger, Used with permission

Things fall apart; the center cannot hold; / Mere anarchy is loosed upon the world, / The blood-dimmed tide is loosed, and everywhere / The ceremony of innocence is drowned; / The best lack all conviction, while the worst / Are full of passionate intensity. WB Yeats

Chaos is deterministic. Nonlinear, yes, but if the initial conditions are known it proceeds like clockwork. Complexity is different, and mich more fun!

@timsoret Well I am not sure that the universe is unpredictable

These pendulums don't look “slightly” different at the start. Here's a snapshot at the start.

kinda reminds me of the pendulum fractal,

Excellent modeling, but it doesn't represent reality. Our universe constantly expands, and nobody knows the boundaries; it could be 14 or 100 billion light years or something else.

We studied double pendula in college, this is a very cool visualization.

It is not chaotic though it may be unpredictable (computational irreducibility) - it is ordered according to the math of bifurcation theory.

You are literally predicting all 812 double pendulums' movement here. This is not a correct example of "unpredictable"

Nature is so math