Fibonacci Gauge can be used in wood working as seen on this video, but I will look this up and built my own to see how it can be applied to painting.
I made this with Balsa wood, which is soft enough to be cut with a sharp Exacto knife. You will need four rivets and those can be found at Ace Hardware store.
I have to say this Fibonacci gauge is a nifty little tool. I have been walking around the house measuring all sorts of things and for the most part there seems to be a pattern in the way measurements repeat and follow this system.
Make your own