Critique Wall.com

Located at the top of the Adobe's Almaden Tower in San Jose, CA, is a LED semaphore. This semaphore was build as a large public art display by New York artist Ben Rubin.

Made up of 4 large wheels a slot or line in the middle, the semaphore was able to represent up to 256 unique characters. When the semaphore began transmission on August 7, 2006, Adobe turned it into a contest. The contest that Adobe sponsored was to decode what message was being sent via the semaphore. In addition to the visual message, they also broadcast an audio transmission over a low-power AM transmitter.

Additionally, since the building is in the flight path of the San Jose airport, every time a plane goes over, the wheels start spinning till after the plane has past.

The contest has been won already, but the website has some great information about the project including some video footage of the building.