Prevalent in the major works of Leonardo Da Vinci and underlying many of his design compositions, is the phi relationship (also known as the Golden Ratio or the Golden Mean), a ratio of approximately 1:1.618, found in nature and creation, and inherent in the Fibonacci sequence. The Golden Rectangle, the Golden Triangle, and the Golden Pyramid, all based on the Golden Ratio are all appear prominent in the work of Leonardo Da Vinci. He referred to the Golden Ratio as the "divine proportion".
Illustrations by Jarek Puczel
3D Street Painting - Poseidon & the Trevi Fountain by Tracy Lee Stum, via Flickr