The Immaterials: Light painting WiFi project visualizes the strength of urban WiFi signals:
A four-metre tall measuring rod with 80 points of light reveals cross-sections through WiFi networks using a photographic technique called light-painting.
The resulting images are quite striking both in terms of their beauty and what they reveal about WiFi networks - that signal quality is highly variable even over a short range. And I thought it was just my WiFi router that was like this.
Learn more about the project, browse the images or watch the video (below).