The Fibonacci sequence is a series of numbers where each number is the sum of the two preceding numbers. It begins with 0 and 1, and the next numbers are generated by adding the two numbers before it: 0, 1, 1, 2, 3, 5, 8, etc. The sequence was introduced to Western mathematics in 1202 by Leonardo of Pisa, also known as Fibonacci. Patterns created by the Fibonacci sequence can be found throughout nature, including in petal arrangements, the seed heads of sunflowers, and the spiral shells of some seashells.