Fig. 4

Left Theoretical robot, seen from above. Note the eight sensors evenly distributed on the perimeter of the robot’s body and the two motors \(L\) and \(R\). The point \(S\) (resp. \(U\)) shows the stable (resp. unstable) facing direction of the light source in the BCM. Right Actual e-puck robot in the same position; the eight proximity sensors (ps0,ps1,...,ps7) are nearly evenly distributed on the perimeter