the.com/fibonacci sequence

means A sequence of numbers where each term is the sum of the two before it (0, 1, 1, 2, 3, 5, 8, 13, 21...), producing growth patterns that turn up astonishingly often in spirals, petals, and branching.

from Named for Leonardo of Pisa, nicknamed Fibonacci, who introduced the sequence to the West in a 1202 arithmetic textbook while actually illustrating a hypothetical problem about breeding rabbits. The pattern itself had already been described earlier by Indian mathematicians studying poetic meter and rhythm. 'Fibonacci' likely comes from 'filius Bonacci' — son of Bonaccio — a surname rather than any reference to numbers at all; the sequence only got his name centuries later, when a 19th-century mathematician popularized it under that label.