It's not quite accurate because it translates three dimensions into two, but this project to render Wi-Fi visible and display the results in a short film is pretty wicked. Conceived of an executed by Timo Arnall, Jorn Knutsen and Einar Sneve Martinussen, Immaterials: Light Painting WiFi is about "investigating and contextualising WiFi networks through visualisation:"

The film is a continuation of our explorations of intangible phenomena that have implications for design and effect how both products and cities are experienced.... Radio and wireless communication are a fundamental part of the construction of networked cities. This generates what William Mitchell called an 'electromagnetic terrain' that is both intricate and invisible, and only hinted at by the presence of antennas.

Check it out:

Immaterials: Light painting WiFi from Timo on Vimeo.

Read more about the project here.