Wet machines and Soft Computers planning road routes organically.
Place your 'problem' in bag and shake to get the answer!
Although done on a simple flat map/surface there is no reason why this couldn't be a 3d model with variable temperatures/variables throughout. The modelling of landscapes can be more accurate organically in order to find target map paths that are efficient from a biologic standpoint.
These types of navigational problems* were among some of the first tackled by 'hard' machines (computers like you are reading this with) when they were first developed and it's nice to see the initially parallel development of bio computing.
* Travelling Salesman problem : What is the shortest route visiting each city exactly once and then returns to the starting city? See more classic computing problems here