The San José Semaphore - Atlas Obscura

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The San José Semaphore

Almaden Tower

It took years to decode its mysterious messages.  


Embedded into the façade of a tall office building in downtown San José, four digital yellow circles rotate every few seconds, seemingly without purpose. This display has gone on since 2006, and it could be easily dismissed as an unusual artistic choice by the resident of the building, the software company Adobe. But in actuality, this light installation, the San José Semaphore, is beaming a code across the city. The artist, Ben Rubin, replaces the code each time it’s cracked, which so far has happened twice.

The first time, two tech workers attending a downtown seminar on how to flirt with girls spotted the Semaphore and spent the next several months breaking down the code. In the summer of 2007, they announced that hidden beneath references to James Joyce’s Ulysses and the Vigenère cipher was the entire text of Thomas Pynchon’s novel The Crying of Lot 49. 

The second time, in 2017, a Tennessee math professor cracked the next code, discovering that the circles had been transmitting an audio recording of the first moon landing. That’s the code still being beamed out over the city, though artist Rubin is, as of early 2021, currently working on a new one. 

Know Before You Go

The San José semaphore is located on the Almaden tower of the Adobe building.

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February 17, 2021

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