Portrait of Adele Bloch-Bauer I, Gustav Klimt, 1907 and the Golden Rectangle

Successive Golden Rectangles dividing a Golden Rectangle into squares (Portrait of Adele Bloch-Bauer I Gustav Klimt).

A golden rectangle is a rectangle whose side lengths are in the golden ratio, one-to-phi, that is, approximately 1:1.618. 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 proportions as the first. Square removal can be repeated infinitely, which leads to an approximation of the golden or Fibonacci spiral.

Fibonacci numbers (0,1,1,2,3,5,8,13,21,34...) are a sequence of numbers named after Leonardo of Pisa, known as Fibonacci. The first number of the sequence is 0, the second number is 1, and each subsequent number is equal to the sum of the previous two numbers of the sequence itself.

Portrait of Adele Bloch-Bauer I is a painting by Gustav Klimt (1862 - 1918) completed in 1907. Klimt took three years to complete the painting. It measures 138 x 138 cm and is made of oil and gold on canvas, showing elaborate and complex ornamentation as seen in the Jugendstil style.

List of most expensive paintings
According to press reports it was sold for US$135 million to Ronald Lauder for his Neue Galerie in New York City in June 2006, which made it at that time the most expensive painting ever sold.