Built one of these about a year ago. Never having heard of the golden mean, I was curious.
Took it around the house measuring vases and other things the wife insists on placing in dangerous places,(while warning about the consequences of breakage).
Was amazed at how many were to this proportion, and the various ways they were to this proportion!!
I'm a believer in using them, but always back off clear my head,
then glance back at the object quickly, to check it by the old I-BALL!!, before applying a finish!