Two Agents in a World of Three Boxes.
The content of the biggest thought balloon represents the model that the Red Shoe Robot has of the world that it inhabits. The robot uses this model when it engages in reasoning about the world, planning actions and when communicating with the Grey Shoe Robot. We can think of the objects in the thought balloon as representing propositions about the world that the robot believes to be true. The black box in the thought balloon represents the fact that the Red Shoe Robot believes there to be a black box on the floor lying underneath a dotted box and next to a blue box. This is seen to be a true belief. The robot does not only have beliefs about the world of boxes, but also beliefs about the beliefs of the second robot. These beliefs about beliefs are called meta-beliefs and are represented within the nested thought balloons. The outermost yellow box represents that the Red Shoe Robot believes the Grey Shoe Robot to believe that among the boxes on the floor there is a yellow one. In other words: the Red Shoe Robot believes the Grey Shoe Robot to have a false belief about the world of boxes, since it believes the Grey Shoe Robot to think that the blue box is yellow. This is a false belief of the Red Shoe Robot, since the Grey Shoe Robot does actually correctly believe the blue box to be blue (see the thought balloon of the Grey Shoe Robot). And so on...