cells-of-a-head
Drawn at its defaults, in packing and tiling.
It carries a slider over angle, 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 3 essays
the blast radius of changing it
Why the average cell has six sides
Not because hexagons are efficient. Because Euler's formula leaves a tiling no choice — count the edges two ways and the mean comes out at six, whatever the cells would prefer. The efficiency argument is a different claim about a different thing.
Packing and tilingPacking, measured four ways
The claim is that the golden angle packs best. It is measurable, and the measurement gives three different winners on three criteria — all near 137.5° and none of them it. That does not make the claim wrong; it makes the usual statement of it wrong.
Packing and tilingThe gap that grows
A rational divergence angle develops an empty wedge that grows without bound as the head fills — a factor of nearly four between two hundred primordia and sixteen hundred. An irrational one does not. That is the statement about the golden angle that survives measurement.