Using A Slime-Mold To Calculate Minimum Spanning Trees 14 years ago
Arxiv has a paper by Andrew Adamatzky (one of the authors of the nytimes article) called "Are motorways rational from slime mould’s point of view?", from 13 Mar 2012, which has pictures:
http://arxiv.org/pdf/1203.2851.pdf
Take a look at page 4.