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Fractal basins of attraction: each color shows which magnet a pendulum released from that point will eventually reach. The boundaries between basins are fractal — infinitely complex at every scale.
The pendulum swings above magnets on a flat plane, pulled by gravity toward center and by each magnet below. Damping slowly removes energy until the pendulum settles at one magnet.
Motter & Lai (2002) "Dissipative chaotic scattering"; also see Peitgen, Jurgens & Saupe (2004) "Chaos and Fractals"