San Jose Semaphore

Artwork by Ben Rubin

The San Jose Semaphore is a public artwork created in partnership with the San Jose Public Art Program. From its position atop Adobe’s Almaden Tower, its four glowing wheels are a beacon on the downtown San Jose skyline. As the wheels slowly turn and come to rest, they send a message that is visible for miles. Like the semaphore telegraphs of the 18th century, the artwork is a large and beautiful machine that uses visible symbols — the positions of its wheels — to slowly transmit information. But even though the Semaphore is broadcasting its message in plain sight, the contents of the message remain a mystery until solved.

 

Each wheel of the Semaphore can assume four positions — vertical, horizontal, left-leaning diagonal, and right-leaning diagonal. Together, the four wheels have 256 possible combinations. The Semaphore transmits its message at a steady rate, with the wheels turning to a new position every 7.2 seconds. Sitting beneath the flight path for the San Jose Mineta International Airport, the Semaphore reacts visibly when a plane flies overhead. The disturbance breaks its rhythm, but when the plane has passed, the Semaphore returns to its steady transmission.

A new code is ready to be cracked.

Two messages have been transmitted and solved since the Semaphore was installed in 2006, and a third unsolved message is transmitting now.

Up for a challenge? A new code started transmission at the top of Adobe’s Almaden Tower on May 11, 2023. The message’s content and the encryption technique used are a mystery open to all to solve. The first person or team to crack the code will be awarded bragging rights and a two-year subscription to Adobe Creative Cloud. Learn more about what’s required to crack the code and rules for participation.

Viewable in person
You can see the Semaphore outside at the top of Adobe’s Almaden Tower in downtown San Jose:
151 S. Almaden Blvd, San Jose, CA 95113

About

In 2001, Adobe broke ground on its third office building — Almaden Tower — on the campus of the company’s world headquarters in downtown San Jose, California. As part of Adobe’s commitment to the city, plans were made to include public art as part of the long-term site development.

In 2003, the San Jose Public Art Program facilitated a process to select an artist for the project. A request for qualifications was submitted to over 100 new-media artists, and 44 artists submitted letters of interest. A panel composed of Adobe representatives and internationally recognized media arts professionals reviewed the artists’ materials and chose a short list for interviews. In July 2003, the panel selected Ben Rubin to design, fabricate, and install the Semaphore artwork for Almaden Tower. Ben Rubin is a leading American artist who pushes the traditional boundaries between art, science, and technology. The San Jose Semaphore began its first transmission on August 7, 2006.

Two messages have been transmitted and solved, and a third unsolved message is transmitting now.

  • First message: The full text of Thomas Pynchon’s 1966 novel The Crying of Lot 49. It was solved by a team of two research scientists, Mark Snesrud and Bob Mayo.
  • Second message: Audio file of “One small step for man, one giant leap for mankind.” It was solved by Jimmy Waters, a high school math teacher from Knoxville, Tennessee.

Adobe’s San Jose Semaphore connects contemporary digital systems with the earliest practical telecommunications network — the Chappe semaphore telegraph developed in France in the late 18th century. The Chappe system employed a visual code created by Claude Chappe and his four brothers that used wooden panels, moved manually by ropes and pulleys, to transmit messages between relay towers 5 to 6 miles apart. Morse code, binary ASCII character representations, Adobe PostScript, and the coding systems used in 21st century digital communications all trace their lineage back to the Chappes’ system for encoding information.

How it works.

The Semaphore consists of four wheels, and each wheel can assume four positions: vertical, horizontal, left-leaning diagonal, and right-leaning diagonal. Together, the four wheels have 256 possible combinations (1 byte of information). The Semaphore transmits its message at a steady rate, with its four wheels turning to new positions — and delivering the next byte of data — every 7.2 seconds.

The Semaphore is illuminated by approximately 24,000 high-brightness LEDs. Artist Ben Rubin worked with Will Pickering of Parallel Development in Brooklyn, New York, to design the artwork’s custom LED driver and display hardware. Each Semaphore disc unit contains a solid-state graphics processor that renders the image of the spinning disc to the array of LEDs. An app written in Max/MSP controls the LED panels across a LAN.

The Semaphore’s steady signal is subject to interference from planes flying overhead. Adobe’s Almaden Tower sits directly underneath the San Jose Mineta International Airport flight path and when a plane flies overhead, it sets the Semaphore discs spinning, causing a momentary break in the transmission.

Crack the code.

There's a new code in town — released on May 11, 2023 — and the challenge to crack it is open.

Semaphore live simulcast

You can see the Semaphore outside at the top of Adobe’s Almaden Tower in downtown San Jose:
151 S. Almaden Blvd, San Jose, CA 95113

Rules

The successful decoder must identify all four parts of the challenge.

  1. The content of the encrypted message
  2.  The original source of the encrypted message
    (For example, if it’s a snippet from a book, you need to name the book.)
  3. The mechanism by which the message is encoded
  4. Your methods for breaking the code, as noted below

There are no restrictions on the methods you use to analyze and break the code, but you must show how you did it.

  • You must show how you recorded the transmission, analyzed the message, and solved the cipher.
  • You must document your process through notes, photographs, and computer source code (if used) and submit these materials with your claim.
  • Use of inside information not available to any resourceful member of the public is grounds for disqualification.

Send your submission to semaphore@adobe.com.

  • To be complete, your submission must include all four parts of the challenge noted above. Partial submissions will not be considered.
  • The first person or team (consisting of no more than five individuals) to accurately submit all four parts of the challenge will be awarded bragging rights and a two-year subscription to Adobe Creative Cloud (valued at US$1,199.76 over two years, as of April 2023). For team submissions, a maximum of five two-year subscriptions will be awarded.
  • The decision to award the winner is at the discretion of Ben Rubin and Adobe.

If you have questions about the challenge, email them to semaphore@adobe.com. Although we won’t be able to respond to each email, we’ll post answers to frequently asked questions and make any essential clarifications there.

NO PURCHASE OR PAYMENT IS NECESSARY TO ENTER OR WIN THIS CONTEST. You must be 18 years of age (or the age of majority in your jurisdiction) or older to participate. No one who is an employee or independent contractor, officer, or director of Adobe, or any of Adobe’s agents and representatives; advertising, promotion, publicity, and fulfillment agencies; legal advisors, successors, and assigns; and any other company or person that is involved with the production, design, execution, administration, or distribution of this Promotion (“Released Parties”) is eligible to enter or win, nor is anyone who lives with (whether or not related), or who is an immediate family member of, any one of the Released Parties (i.e., parents, siblings, children, and children’s respective spouses, regardless of where they reside). The Promotion is subject to all applicable federal, state, territorial, provincial, municipal, and local laws and regulations and is void where prohibited or restricted by law. The sponsor of the Promotion is Adobe Inc., 345 Park Avenue, San Jose, California, 95110, United States.

FAQ

It’s located at the top of Adobe’s Almaden Tower in downtown San Jose, California, on the outside of the building’s 18th and 19th floors. The Semaphore is visible from Highway 87 and parts of downtown San Jose.

Adobe Almaden Tower
151 S. Almaden Blvd
San Jose, CA 95113

You can see the Semaphore only from outside the building or online.

The Semaphore operates every day from 7am until midnight (Pacific Time). The web simulcast operates around the clock.

The Semaphore is 70 feet (21.3 meters) wide and 10 feet (3 meters) high.

The soundtrack for the semaphore can be heard as part of the Semaphore’s online transmission. The audio supplements the information transmitted visually, and it might be helpful in decoding its message. The soundtrack is composed of several layers: a mechanical-sounding tick of the disks as they turn and come to rest, musical beeps and tones, and voices recorded by the artist. One voice is the artist’s friend Elisa Zuritsky singing numbers, and the other is sampled from a short-wave radio broadcast of an encrypted Cold War–era “numbers station” transmission that the artist recorded while on a trip to the Middle East in 1990.

The message is encrypted, and until the code is cracked, the message isn’t publicly shared. We invite you to crack the code!

A semaphore — sometimes called an optical telegraph — is a device that uses visible signals or symbols to transmit information. Common examples of semaphores include traffic lights and railroad signals. Before the telegraph, semaphore signaling systems (including moveable wooden panels, flags, and signal fires) were the fastest way to communicate messages over a long distance.

In 2001, Adobe broke ground on its third office building — Almaden Tower — on the campus of the company’s world headquarters in downtown San Jose. As part of Adobe’s commitment to San Jose, plans were made to include public art as part of the long-term site development. In 2003, Adobe worked with the San Jose Public Art Program to select Ben Rubin, a leading American new-media artist, to design, fabricate, and install the Semaphore artwork for Adobe’s Almaden Tower. The Semaphore began its first transmission on August 7, 2006.

Recognition will be posted on this website and on Adobe-owned social media channels. The first person or team (up to five individuals) to send a complete and accurate submission will be awarded bragging rights and a two-year subscription to Adobe Creative Cloud (valued at US$1,199.76 over two years, as of April 2023). Learn more about what needs to be included in a submission and rules for participation.

Send an email to semaphore@adobe.com.

Alamaden Tower

Credits

San Jose Public Art Program

The San Jose Public Art Program seeks to build community identity by initiating artworks and exhibitions that enhance the civic landscape. Through active community engagement with artists, public art projects strive to reflect the city’s ethnic diversity and historic richness, and envision its present and future. The Public Art Program is a division of San Jose’s Office of Cultural Affairs.

Artist

New York–based artist Ben Rubin creates media installations, projections, and theatrical designs for museums, public spaces, and live performances. From 2015 to 2020, Rubin served as director of the Center for Data Arts at The New School, where he developed advanced techniques for data visualization and sonification. Rubin received his BA in computer science and semiotics from Brown University in 1987 and his MS in media arts and science from the MIT Media Lab in 1989. Rubin’s work has been exhibited at the Museum of Modern Art and the Whitney in New York as well as numerous international venues.

Engineering and fabrication

Will Pickering of Parallel Development Ltd. provided services for the San Jose Semaphore.

Live simulcast web app (2023)

Alex Zisis

Additional Semaphore production credits

Design associate: Peter Zuspan / Graphics firmware and additional software: Paul Paradiso / Project electrician: Alan Wieteska, Cupertino Electric / Fabrication and machining: Patrick Gavin, Parallel Development / Voices of the Semaphore: anonymous (speaking), Elisa Zuritsky (singing) / Special thanks to Mark Hansen and Dan Wallach for their assistance in developing the Semaphore’s original encoding scheme.