According to some religious beliefs, an angel who fell from the sky took the form of a peacock. And the eye-like patterns on the peacock’s wings are the eyes of the angel through which he can see this world. There is a beautiful book about those magnificent birds, Why Peacocks?: An Unlikely Search for Meaning in the World’s Most Magnificent Bird.
James Gyre, the owner of “Naked Geometry,” was curious about a peacock’s tail. So he analyzed the geometry of the peacock’s tail-feather display. It turns out the shape is a symmetrical phyllotaxis, which is somewhat surprising. Although most phyllotaxis patterns in nature, like on pinecones, pineapples, and sunflowers, have spirals of adjacent Fibonacci numbers, the peacock’s feathers have the same count of spirals; in both directions!
If you want to see more beautiful geometry examples in nature, you should check out Rafael Araujo’s Mesmerizing Geometrical Drawings Using Golden Ratio.