Came across this today in the tech news sites. Its a mapping algorithm based on Djikstras algorithm of visiting every node once thing. I thought it was interesting since it is basically optimising the paths for shortest distance which is not so dissimilar to mapping using economics which was also optimizing based on most profitable / least costly basis too which I had a go at a few years back. I am sure that there is some big reward to whomever cracks this nut !

https://github.com/ibaaj/dijkstra-cartography

Its github so go get that source and play with it.