Despite its ability to solve an array of problems, the slime mold was designed by evolution to solve just one problem: how to build an optimal transport network (for its nutrients). So we decided to investigate how the slime mold, when presented with the task of connecting the major urban areas of the United States, would design a transport system. Would its design resemble that of the United States highway system, or would the slime mold propose a superior one?
Here’s how our experiment worked. As we detail in a forthcoming article in the journal Complex Systems, we took a large dish in the shape of the United States and placed rolled oats (a food for the slime mold) in the locations of 20 major urban areas. Then we put the slime mold on the rolled oats representing the New York area. The slime mold propagated out from New York toward the other urban areas and eventually spanned them all with its network of protoplasmic tubes. We performed this experiment a number of times.
What did the resulting network look like? It looked remarkably like the United States interstate highway system.