Credit cards are in the shape of a Golden Rectangle. If you ever need an easily accessible example of a golden rectangle illustrating the proportions of the golden section, all you need do is to pull out a credit card or drivers license.
Standard sized credit cards are 54mm by 86mm, creating a ratio of 0.628, less than a millimeter off from a perfect golden ratio or golden section of 0.618, the reciprocal of 1.618.
