Golden Ratio Caliper
The Golden Ratio is a universal mathematical constant, much like e or π. It is approximately equal to 1.618 and represented by the Greek letter Phi (φ).
It has been extensively studied by mathematicians and used by architects and artists alike for thousands of years. Examples of approximate golden ratio spirals can be found throughout nature in leaves, flowers, seashells, pinecones and spiderwebs.
The distance between the arms of these calipers will always measure the golden ratio, regardless of size.