Enterprising Elegance The rule of 72 is a formula that estimates the amount of time it takes for an investment to double in value. As a back-of-the-envelope calculation, one simply divides 72 by the annual interest rate.rule of 72 is a tribute to the world of corporate elegance, money, calculations,suits, and sunglasses. Your rule, your risk. The muted elegance of saffron and geranium meets the vigor of natural Thai oud and creamy guaiac wood from Paraguay. Leather notes paired with vetiver and patchouli lend this composition the right amount of calculated determination, completing this modern approach to luxurious solitude.Use:Use and spray as much as you desire 2787 Perfumes Rule of 72 27 ml