Roomba Pattern

We've got a Roomba 530 for a while now - Roombas are vacuum robots, about the size of a Vinyl LP, as high as a good Webster Dictionary. It did it's duty on our hardwood floor area in the 1st floor. Right now it is not running regularly since there is a suspicion that it would leave marks on the walls, and we have to lift the oversize curtains so that these would not be eaten. Anyway, I come to this topic since I found via Engadget a site that shows how the Robot traverses the room. This looks like a secret map, leading to something... a treasure at least, or aliens?