Engineers in Tokyo revamped the rail lines from Tokyo to its surrounding cities to make it more efficient. Some researchers wanted to test the efficiency of those routes and did so by transposing a scaled down version of the map onto a growth medium. A slime mold (type of fungus) was placed in the center of the medium, corresponding to where Tokyo would be. Oat flakes, a nutrient source for slime molds, were placed on the medium, scaled to correspond to the cities that surround Tokyo. The slime mold grew towards the oat flakes in order to feed off of them and over time funneled into the most direct and efficient paths towards their nutrient source. When compared to the most efficient routes that they engineers came up with they were found to be comparable.
This is one example of the ways in which biomimicry, and the concept of designing from patterns to details, can be used in smart growth design. As global population increases our cities will become more crowded and with that growth will come challenges in design. The slime mold experiment is a low-tech and time efficient tool to map out potential navigation routes.
The larger point here, though, is that we have so much to gain from tapping into the wisdom of the natural world. The more we can identify patterns in nature the better we will be able to design. The more place-based we can make those patterns, the more we will be able to customize design for specific geographic areas.
For a more in-depth read on the Tokyo slime mold experiment, see this 2010 Wired article.
As a follow-up read, this Guardian article from 2014 further explores the ways in which studying slime molds in mapping can provide us with efficient design ideas for different sectors of society. It discusses some of the gaps in our understanding of slime molds' behaviors, especially around the concepts of anticipatory behaviors and intelligence.
