San Jose Semaphore

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.

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.

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.

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

• 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.

• 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.