Exploring the Fibonacci Sequence With Python (Overview) – Real Python

The Fibonacci sequence is a series where each number is the sum of the two numbers before it: 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89… In nature, this sequence appears in the spiral arrangements of many plants. In a sunflower head, the seeds are packed in two sets of spirals curving in opposite directions. The counts of these spirals match consecutive Fibonacci numbers — for example, 13 and 21 seeds on this sunflower head, or higher pairs on larger heads, like 34 and 55, 55 and 89, and so on. This

Nature and Math: The Fibonacci Sequence - Herbert F. Johnson Museum of Art