A model-driven visual study of fractal basins of attraction.
MOVING IMAGE — THE ATLAS RESOLVESγ 0.15 · d 0.3 · one pendulum per pixel · lodestone
WHAT IS THIS
A steel pendulum swings above three magnets. Friction slowly drains its energy until it hangs over one of them — but which one is practically unpredictable: releases a hair's-width apart end on different magnets. This study colours every possible starting point by its final magnet, turning the plane into an atlas of fate whose three territories interlock along a fractal boundary (a "Wada" boundary: every point of it touches all three).
The model is the standard planar magnetic pendulum — friction, a restoring pull toward the centre, and three regularised magnetic wells. This study integrates one pendulum per pixel on the GPU (about a million at once) and runs in real time, so the map visibly resolves out of the undecided shimmer.
the atlas — the classic three-magnet fate mapγ 0.15 · d 0.3 · ω₀² 0.5 · window 2.4 · lodestone
MethodA small simulator was generated and modified with AI assistance, then ported to a real-time GPU (GLSL) renderer. The visual output was selected through parameter exploration.
ObservationFriction is the dial of fate: heavy damping cuts the plane into three smooth territories, light damping shatters the boundary into fractal filaments (uncertainty exponent α ≈ 0.62, D_b ≈ 1.38). Raising the magnets births a fourth, magnet-less fate — rest at a silent equilibrium. The longest-hesitating points glow brightest: the shining part of the map is exactly where fate cannot be told.
ReferenceS. W. McDonald, C. Grebogi, E. Ott & J. A. Yorke, "Fractal basin boundaries," Physica D, vol.17, 125-153 (1985).
This is not a scientific simulation result, but a visual interpretation of the phenomenon.
THE SAME FAMILY, A DIFFERENT QUESTION
Lorenz follows one orbit. This study asks all of them at once.
Study #05 — LorenzStudy #15 — Pendulum basins
The questionwhere does one orbit go? — a single trajectory, followed foreverwhere does every start end? — a million trajectories, asked once each
What is drawnthe path itself, accumulated into orbit densityonly the verdict — each start coloured by its final magnet
The chaosnever settles — sensitivity along one endless pathsettles every time — the sensitivity lives in which end you get
PARAMETERS EXPLORED
parammeaningeffect on the image
γfriction — the dissipation ratethe fractality dial: heavy damping gives three smooth lobes, light damping shatters the boundary into filaments that invade the whole map
dthe bob's height above the magnet planethe sharpness of the wells — raised high, a third kind of rest appears away from every magnet, woven in as pewter ribbons (the null fate)
ω₀²the restoring pull toward centretightens the map inward and raises rings of equal settling time around the rim
Nthe number of magnetsthe map's symmetry — 3 the classic Wada atlas · 4 a compass chart · 5 a rosette
windowthe frame of the mapzoom — the boundary holds structure at every magnification
settle timehow long each start hesitated (measured)the brightness — undecided points glow, so the fractal boundary is the shining part
Each image below records its exact parameter set.
SELECTED STILLS — 6
the atlas — three fates interlockedγ 0.15 · d 0.3 · window 2.4 · lodestone
the null fate — pewter ribbons where the bob stops over no magnetγ 0.18 · d 0.5 · lodestone
shore — every coastline hides another atlasγ 0.15 · window 0.75 · centre (0.9, 0.9)
PROCESS — PARAMETER SWEEPS
Friction γ against magnet height d — the phase map of fate. Down the friction axis the boundary shatters from smooth pie to all-invading filigree; along the height axis the fourth, magnet-less fate is born.
the γ × d morphology maprows = γ (friction) · columns = d (magnet height)
SIGNATURE — WHERE FATE CANNOT BE TOLD, IT SHINES
The boundary is measured, not just admired.
Brightness in these maps is hesitation: each point glows by how long its pendulum wavered before settling. The fractal boundary — where releases a hair's-width apart end on different magnets — is therefore the part that shines. The map's darkness is certainty; its light is doubt.
And the doubt is quantified: the uncertainty exponent of McDonald-Grebogi-Ott-Yorke, measured inside this model as α ≈ 0.62, gives the boundary dimension D_b ≈ 1.38 at the hero's friction — final-state sensitivity made visible, then measured.
how to read the atlas — colour is fate, brightness is hesitationα ≈ 0.62 · D_b ≈ 1.38 · isochrones = swings needed
COLOUR = IRON OXIDES
The three basins are painted with the three iron-oxide pigments — hematite red (Fe₂O₃), goethite ochre (FeOOH), magnetite blue-black (Fe₃O₄). This is the magnet's own mineral chemistry: magnetite is lodestone, the first magnet humanity ever knew — and these same oxides were the first pigments humanity ever painted with. A map of magnetism, painted in magnetite's family colours.
Brightness maps settle time — hesitation glows — and the pewter regions are a real fourth fate: equilibria where the bob stops away from every magnet.
the fourth fate in pewter — rest, over no magnet at alld 0.5 · null-fate ribbons + centre pupil · lodestone
Pigment hues are artistic approximations of the minerals, not measurements.
REFERENCES
S. W. McDonald, C. Grebogi, E. Ott & J. A. Yorke, "Fractal basin boundaries," Physica D, vol.17, 125-153 (1985).
A. E. Motter, M. Gruiz, G. Károlyi & T. Tél, "Doubly Transient Chaos: Generic Form of Chaos in Autonomous Dissipative Systems," Physical Review Letters, vol.111, 194101 (2013).