Choose square (90°) or triangle (60°) segments Ratio of consecutive lengths approximates Phi
Each # in the sequence = sum of the prior two Ratio of the two is ~Phi (1.608... or 0.608 ....) Phi is a very irrational number Each section's length is the current # The list of #s called Fibonacci sequence I had done earlier versions without triangles The "Fibonacci rectangle" with its 90° squares is a human-made visualization of the sequence. Nature (say a snail shell) doesn't use those squares or count integers. A snail's shell—and the chambers within a nautilus—grows as a continuous logarithmic spiral, nothing to do with the golden ratio. The man made quality of the geometric squares is evident too when we use triangles. We found those shapes look pretty and neat. You could use other shapes.
