This amazing number was known to Euclid and its properties have been studied through the ages, even to the present day. Now known as F (phi), it equals the sum of one plus its own reciprocal, or its own square minus one, but it approximates 1.61803... . At least one book has been written about it, and it has been said (probably wrongly) to have dictated the proportions of the Parthenon.
Here we offer products showing one of its best-known manifestations, the "whirling squares", with an Archimedean spiral - the curve of every spiral shell - drawn on each, in gold, of course.
