The arms of Calipers open and close to measure different distances.
The ratio between the two distances is always 1 : 1.618
The ratio between the larger distance and the overall arm-span is also 1 : 1.618
Here is a video I made about 5 years ago, which I’ve been trying to get around to updating ever since…
Since then, a couple of other people have made videos using my calipers… which I’ll embed – hope they don’t mind :)
1) Daria Chuprys – permanent makeup-artist extraordinaire, from Beverly Hills, CA – demonstrating the different measurements that go into making the perfect eyebrow.
2) Another video showing the basic operations with regards simple (or not so simple) geometry here:
Even after all these years, I still find it quite astonishing that the dimensions of the human face and the the mathematical precision of geometry should be so intimately linked.