Continued fraction convergent — where it appears
Named by 2 essays across one field — each of them below, with the objects they name alongside it.
The counts change with radius
The same head gives 13 and 21 near the centre, 21 and 34 further out, 34 and 55 beyond that, and 55 and 89 at the rim. The transitions are at computable radii, and a photograph captioned with one pair is a statement about one annulus rather than about a flower.
Every family but two is a sum
A seed head has six spiral families and everybody reports two. That looks like a convention hiding information and it is the opposite — every family but the two smallest is the sum of two others, so a third count is a prediction rather than a measurement, and a check that catches a wrong pair.
Named alongside it
The objects these essays reach for when they reach for this one.
Continued fractionFibonacciLattice offsetAnnulusCounting blindBranchDelaunayDivergence angleGolden angleLatticeLucas numbersMeasurement