Oak Park in Cook County, Illinois — The American Midwest (Great Lakes)

Fibonacci

Photographed by Sean P. Flynn, April 14, 2026

1. Fibonacci Mural, part 1

Inscription.
the Golden Ratio is used in ancient and modern buildings

the original problem Fibonacci investigated was about breeding rabbits. how many pairs of rabbits would breed in one year?

Discovered in 1202
how many whirls in the pine cone?
how many scallops on a shell?
how many petals on a flower?
how many whirls in a sunflower?
how many legs does a sea star have?
how many whirls in a pineapple?

Golden Ratio 1.618
Φ

Fibonacci (a.k.a. Leonardo Pisano Bigillo), an Italian mathematician studied the laws and patterns of nature. Investigated the way rabbits multiply, discovered that successive numbers added together and divided by each other give a ratio of 1.618. Artists, architects & scientists consider these divine proportions the key to beauty.

the sequence begins:

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1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144...

Leonardo Pisano Bigollo
c1170-1250
A Treasure of our time

Erected 2011 by Oak Park Education Foundation.

Topics. This historical marker is listed in these topic lists: Architecture • Arts, Letters, Music • Environment • Science & Medicine. A significant historical year for this entry is 1202.

Location. 41° 53.222′ N, 87° 48.018′ W. Marker is in Oak Park, Illinois, in Cook County. It is at the intersection of Home Avenue and South Boulevard, on the right when traveling north on Home Avenue. Touch for map. Marker is in this post office area: Oak Park IL 60301, United States of America. Touch for directions.

Regionally, this marker is in Greater Chicago.

It is also in the American Midwest

and on the Great Lakes.

Globally, it

Fibonacci Mural, part 2 image. Click for full size.

Photographed by Sean P. Flynn, April 14, 2026

2. Fibonacci Mural, part 2

is in North America,

the Western Hemisphere,

the Western World,

and the Anglosphere.

Historically, it finds itself in what was once the Viceroyalty of New France,

the territory of the Mississippian Culture,

and the Northwest Territory.

Other nearby markers. At least 8 other markers are within walking distance of this marker: Henrietta Lacks (a few steps from this marker); Pleasant Home (about 500 feet away, measured in a direct line); Oak Park Station (about 500 feet away); Mills Park and Pleasant Home (about 600 feet away); James Russell Lowell School (about 600 feet away); Continental Divide (about 600 feet away); a different marker also named Mills Park and Pleasant Home (about 600 feet away); Niles Building (about 700 feet away). Touch for a list and map of all markers in Oak Park.

More about this marker.

Fibonacci Mural, part 3 image. Click for full size.

Photographed by Sean P. Flynn, April 14, 2026

3. Fibonacci Mural, part 3

The mural was painted onto the train embankment by a 2011 youth summer camp sponsored by the Oak Park Education Foundation (OPEF). A mural across the street, dedicated to the Henrietta Lacks, was painted by OPEF campers in 2012. A few other murals can be found in Oak Park train tunnels, including one dedicated to Marie Curie.

The mural demonstrates a fair bit of wear in parts, including some smaller sections that have been painted over. Half of the painting of Fibonacci himself on the south end of the mural has been painted over; the words beneath it were determined based archived images from Google Maps Street View.

Also see . . .
1. Train embankments are Oak Park’s new canvass.

Excerpt: "Last summer, under the tutelage of Phyllis Frick, a sixth-grade science teacher at Brooks Middle
Photographed by Sean P. Flynn, April 14, 2026

4. Fibonacci Mural, part 4
School, the class introduced the equations of 13th-century European mathematician Leonardo Pisano (aka Fibonacci) to Oak Parkers through a mural illustration depicting his answer to the following mathematical puzzle:

"A certain man put a pair of rabbits in a place surrounded on all sides by a wall. How many pairs of rabbits can be produced from that pair in a year if it is supposed that every month each pair begets a new pair, which, from the second month on, becomes productive?

"You can find the answer on the east wall of the underpass. It is known as the Fibonacci Sequence: 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144 … etc. What Fibonacci discovered was that successive numbers, added together and divided by each other, gives a ratio of 1.618, as the wall caption explains. Artists, architects
Photographed by Sean P. Flynn, April 14, 2026

5. Fibonacci Mural, part 5
and scientists alike consider these divine proportions to be the key to beauty. In this rendering, the concept is demonstrated through the spiral imagery of a sunflower, a pineapple and human growth."

(Submitted on April 15, 2026, by Sean P. Flynn of Oak Park, Illinois.)

2. Nature and Math: The Fibonacci Sequence in Nature. From Cornell University's Johnson Museum of Art. (Submitted on April 15, 2026, by Sean P. Flynn of Oak Park, Illinois.)

Fibonacci Mural, part 6 image. Click for full size.

Photographed by Sean P. Flynn, April 14, 2026

6. Fibonacci Mural, part 6

Photographed by Sean P. Flynn, April 14, 2026

7. Fibonacci Mural, part 6

A view of the Fibonacci mural's south end from across the street image. Click for full size.

Photographed by Sean P. Flynn, April 14, 2026

8. A view of the Fibonacci mural's south end from across the street

Credits. This page was last revised on April 15, 2026. It was originally submitted on April 14, 2026, by Sean P. Flynn of Oak Park, Illinois. This page has been viewed 17 times since then. Photos: 1. submitted on April 14, 2026, by Sean P. Flynn of Oak Park, Illinois. 2, 3, 4, 5, 6, 7, 8. submitted on April 15, 2026, by Sean P. Flynn of Oak Park, Illinois.