Callipers for finding the Golden Ratio.
The golden ratio has fascinated Western intellectuals of diverse interests for at least 2,400 years:
Some of the greatest mathematical minds of all ages, from Pythagoras and Euclid in ancient Greece, through the medieval Italian mathematician Leonardo of Pisa aka "Fibonacci" and the Renaissance astronomer Johannes Kepler, to present-day scientific figures such as Oxford physicist Roger Penrose, have spent endless hours over this simple ratio and its properties. But the fascination with the Golden Ratio is not confined just to mathematicians. Biologists, artists, musicians, historians, architects, psychologists, and even mystics have pondered and debated the basis of its ubiquity and appeal. In fact, it is probably fair to say that the Golden Ratio has inspired thinkers of all disciplines like no other number in the history of mathematics.
- Mario Livio, The Golden Ratio: The Story of Phi, The World's Most Astonishing Number
- wikipedia : http://en.wikipedia.org/wiki/Golden_ratio
These need to be made in something that can be tightly joined (ie: bolted or riveted) eg, stainless steel or brass.
I have completed (finished, riveted etc) stainless steel callipers available for sale here - if you want the designs though - feel free.