The Perfect Subway Network

This image is courtesy of Wired magazine.  In a recent article, author Brandon Keim explored the relationships between the use of a subway system and its physical structure / urban planning.  What would the ideal shape of movement be?

http://www.wired.com/wiredscience/2012/05/subway-convergence/

In a related article linked to this one, slime molds were also held up as an example of how the actual network shape of a national road system might be determined by how mold grows over a surface.  In this case, the shape of the surface is the country itself:

http://www.wired.com/wiredscience/2011/05/slime-mold-iberia/