Craig Taylor from Ito World used a coral metaphor to visualize road networks in major cities around the world:
For the past six months I have been fascinated by the concept of making city networks look like living corals. The varying patterns of urban forms are inherently dictated by their road network; a complex, seemingly organic connection of links moving people across their city. Like branches of coral they have a pattern and a function, I chose to expose this pattern and manipulate it to become something far more conceptual. However, whilst being incredibly beautiful they are derived from various geo-spatial analysis of drive-times catchments making them somewhat informative as well.