The Fibonacci Series is a self-replicating sequence of numbers that is derived by adding the two prior numbers to generate the next one: 0,1,1,2,3,5,8, and so on. If you take two adjacent numbers and divide the smaller into the larger, the result approximates Phi (also know as the Golden Section or Golden Mean) with increasing accuracy the higher into the series.

The Fibonacci numbers appear throughout nature, including: the family tree of honey bees; shell spirals; the branching and leaf arrangements of plants; and the arrangement of seeds on flower heads such as sunflowers.

1:2:3:5:8 can be described as both geometric and organic. The blocks are clearly geometric in form and yet, they are also organic in that their dimensions and arrangement are derived from proportions and patterns found in nature.