The slime mould approach to urban planning. Is it an idea that will go viral?
Update: there is now a video
Two researchers - one from the UK and one from Canada - have put the slime mould Physarum polycephalum to work as an analog computer.
There are two ways to solve any problem using a simulation you can use analog or digital methods. Analog methods have been out of fashion for some time but they could be about to return if the slime mould approach catches on.
The idea is based on the observation that the slime mould in question works co-operatively to create networks that transport nutrients from one location to another.
So what do you do with this observation?
You create a growth medium the shape of Canada and place rolled oats (selected to be of an appropriate size) to represent major urban areas. Then you let the slime mould grow to create a protoplasmic network that simulates the road network of Canada.
You can see one outcome of the experiment below.
Of course being a living system it rarely repeats the solution it finds. To give a representative result the experiment is repeated and a weighted graph constructed showing frequency that a tube is created. The weighted graph can then be thresholded to give a solution for the optimum connections between cities.
It is claimed that the result approximates the real Canadian highway network.
To improve the results so that roads avoid particular locations, e.g. the location of the Bruce Nuclear plant, single crystals of sea salt were placed on the agar Plans for further work include using contaminants to model terrain and other planning conditions. Placing nutrients and contaminants in more controllable concentrations would provide a more accurate way of programming the slime mould computer.
Given that the slime mould tends to construct minimum energy transport networks this is clearly a method that could be generalised.
You can see a time lapse video of the mould growing below:
So if you find yourself complaining about the road system, electricity grid, water distribution ... it might be a slime mould you have to blame.
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