In math, the Fibonacci sequence begins with 0, then 1, then progresses such that each subsequent number is the sum of the previous two, thus ~
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144 ....
If one draws successive squares with sides of those dimensions, one arrives at a spiral, sometimes called the golden ratio ~ a shape which is widely present in the physical world, from the very small (the curl of a fern leaf, the seed patterns in a sunflower, the compartments of a chambered nautilus) to the very large (the shapes of hurricanes and galactic arms). See the above image ~ click to enlarge.
Evidence of intelligent design? Hardly. One of the guiding principles of science is parsimony, also known as Occam's razor ~ that is, among competing hypotheses (proposed explanations for a phenomenon), the one with the fewest assumptions is most likely to be accurate. The highly complex hypothesis of a deity is superfluous, since it has been shown repeatedly that matter and energy spontaneously adopt the form or path that is most efficient ~ like the hexagons in a bee's honeycomb. Similarly, among growing organisms and among accreting energy systems, the golden ratio spontaneously forms because it is simple and natural.
Even intricate systems like fractals are hyper-branching elaborations of simpler shapes. They, too, appear in nature ~ self-similar patterns repeating at different scales, like an aerial view of a coastline or a river network, or a microscopic view of a snowflake.
Isn't life grand?