The problem is to form a fence around the beacons (the circular objects) using the bars that are scattered around the world.
Our bot first builds a graph to describe the world (the time consuming bit), then searches the graph for paths connecting goals.
The Prolog code can be found here, or can be downloaded with the applet source from the prolog page.
If you're trying to run the application, invoke it like so:
./run -l bot.serin the