I wouldn't say 'just like'. There were some differences. The slime mold has to worry about its connections getting severed, so there were some extra edges which are redundant.
This is because the Tokyo Rail System engineers didn't have the same concerns, that tunnels would suddenly get cut off and blocked.
http://www.wired.com/wiredscience/2010/01/slime-mold-grows-n...
Original article: http://www.sciencemag.org/content/327/5964/439.abstract