Concept
Claim testing — where it appears
2 essays name this object, across 2 fields. What follows is each of them, and the objects they name alongside it.
The claim that survives
Of the three famous assertions about this subject, one is out by a factor of two, one is true of a branch rather than of plants, and one is right — in a sharper form than the version usually told, and about arithmetic rather than about packing.
The nautilus question
A golden spiral grows by 6.854 per turn. Measured nautilus sections give about 3.2. That is a factor of 2.14 — not a rounding error, not an artefact of where the centre is assumed to be, and not close.
Named alongside it
The objects these essays reach for when they reach for this one.
BranchFibonacciφ, the golden ratioApproximationContinued fractionConvergentsDivergence angleGolden spiralGrowth factorHurwitz's theoremLogarithmic spiralMeasurement sensitivity