Slime mold and highways

You may have read about the experimenters in the UK who have put slime mold into boxes shaped like various countries or cities, put food at the nodes, and then watched what happened. . . . the slime mold recreated the US highway system, or the Tokyo transit system, to name just a couple. n case you find it hard to believe from the still pictures, here's a video of slime mold recreating the Canadian highway system.