Fibonacci rules...

Echinacea purpurea, purple coneflower

A coneflower whorl is a lovely example of the Fibonacci series. That's the sequence of numbers created by adding together the previous two numbers starting with 0 and 1. So that gives you -- 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, and so on. Dividing two successive numbers (especially as the numbers get larger) gives the golden ratio or golden mean, which has long been a favorite device in art because of its aesthetically pleasing proportions.

But that orange against the purple ain't half bad either!!