In a project entitled Immaterials: Light painting WiFi, three designers in Oslo wanted to make visible the data that is normally unseen to us. They created a four-metre tall measuring rod with a number of LED lights and network detectors that would measure the strengths of WiFi networks in different parts of the city.
The number of lights that would light up on the rod corresponded to the signal strength in the area they would be in, and using long exposure the designers were able to visualize the WiFi networks they encountered. Check out the video of their project.
[via Laughing Squid]