Phyllotaxis 3D: Golden-Angle Growth Spiral

This simulation renders a real three-dimensional phyllotaxis structure — not a flat spiral — that you can freely orbit and zoom through while primordia (seeds, florets or leaves) appear one at a time, each rotated by the golden-angle divergence (~137.5°) from the last. In Disc mode it ports the 2D original's exact Vogel-model recurrence, radius = C·√n at angle n·divergence, onto a domed 3D capitulum like a real sunflower head. In Helix mode the same divergence angle instead climbs a central stem at a fixed internode rise per leaf — the general, fully three-dimensional form of the phyllotaxis rule that governs ordinary leaf arrangement. Sweep the divergence angle away from 137.5° to see the tight interleaved spirals break down into straight radiating rays, which is exactly why the golden angle is special.