A golden rectangle is one whose side lengths are in the golden ratio , , which is (the Greek letter phi ), where is approximately 1.618. A distinctive feature of this shape is that when a square section is removed, the remainder is another golden rectangle ; that is, with the same aspect ratio as the first. Square removal can be repeated infinitely, in which case corresponding corners of the squares form an infinite sequence of points on the golden spiral , the unique logarithmic spiral with this property. According to astrophysicist and mathematics popularizer Mario Livio , since the publication of Luca Pacioli 's Divina Proportione in 1509, when "with Pacioli's book, the Golden Ratio started to become available to artists in theoretical treatises that were not overly mathematical, that they could actually use," many artists and architects have bee...