Phyllotaxis
the spirals are counted, not admired
Generator

stem-unrolled

The counter is shown these coordinates and the circumference, and finds 2 parastichies one way and 3 the other. The faint strips left and right are the same stem: a family leaving one edge re-enters at the other.
A stem unrolled: 90 nodes at 137.51° with a rise of 0.090 circumferencesThe counter is shown these coordinates and the circumference, and finds 2 parastichies one way and 3 the other. The faint strips left and right are the same stem: a family leaving one edge re-enters at the other.2 and 3rise 0.106 · divergence 137.51°counted 2 and 3, opposed

Drawn at its defaults, in stems, and the ladder. It carries a slider over rise, so the claim in its caption strip is restated at every stop rather than at one. It takes no options at all, so every essay calling it gets this exact drawing.

Called by 1 essay

the blast radius of changing it

Stems and cones

A stem is a cylinder

The sunflower is the photograph, and it is the hard case. Nearly all real phyllotaxis happens on a stem, where the geometry is a lattice on a cylinder with two parameters — and where the spiral counts, which on a disc change with radius, are the same the whole way up.

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