Fibonacci Sunflower

Golden angle = 360° × (1 − 1/φ) ≈ 137.508° where φ = (1+√5)/2 is the golden ratio. Each seed is placed at angle n × 137.508° at radius √n — simple but produces the most uniform packing possible. The number of visible spiral arms is always a Fibonacci number (13 clockwise, 21 counterclockwise, or 34/55 etc.). This is because φ is the "most irrational" number — hardest to approximate by rationals — so spiral arms never line up. Sunflowers, pine cones, artichokes, and nautilus shells all use this principle. Drag the angle slider slightly off 137.508° to see it break into visible arms.