CURIOSITY

Some commonly used objects, such as credit cards, mobile phone SIM cards, Neapolitan playing cards, are golden rectangles, in which the ratio between the base and the height approximates the golden number φ = 1.618...:

Neapolitan playing card.

Front view of a typical credit card.

It should be added that the golden ratio, due to the sense of harmony and balance it conveys, has been used in the design of many successful logos. Some examples are given by the logos of National Geographic, Apple, Twitter, McDonald's, Pepsi, Toyota, Chevron: