"Fibonacci sequence." YourDictionary, n.d. Web. 12 December 2018. <https://www.yourdictionary.com/fibonacci-sequence>.
Fibonacci sequence. (n.d.). Retrieved December 12th, 2018, from https://www.yourdictionary.com/fibonacci-sequence
A sequence of numbers, such as 1, 1, 2, 3, 5, 8, 13 ... , in which each successive number is equal to the sum of the two preceding numbers. Many shapes occurring in nature, such as certain spirals, have proportions that can be described in terms of the Fibonacci sequence.