GoGeometry The Golden Rectangle and The Lighthouse or The Pharos of Alexandria, Egypt

Successive Golden Rectangles dividing a Golden Rectangle into squares (The Lighthouse or the Pharos of Alexandria, hand-colored engraving by Martin Heemskerck, 1498-1574).

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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.

The lighthouse of Alexandria  or The Pharos of Alexandria was a tower built in the 3rd century BC (between 285 and 247 BC) on the island of Pharos in Alexandria, Egypt to serve as that port's landmark, and later, its lighthouse. With a height variously estimated at between 115 ~ 150 meters (377 ~ 492 ft) it was among the tallest man-made structures on Earth for many centuries, and was identified as one of the Seven Wonders of the World by Antipater of Sidon.

It may have been the third tallest building after the two Great Pyramids (of Khufu and Khafra) for its entire life. Some scholars estimate a much taller height exceeding 180 meters that would make the tower the tallest building up to the 14th century.  


The Lighthouse or the Pharos of Alexandria