The golden angle

Each new seed turns by the same angle from the last and sits a little further out. At 137.508°, a full turn divided by φ², the seeds pack evenly with no gaps, and the spirals you can count come in Fibonacci numbers; at a simple fraction of a turn they line up in straight spokes. Nudge the angle a tenth of a degree away and the outer seeds go first, bunching into arms with gaps between; the more seeds, the smaller the error that shows.