The first animation (and perhaps the simplest for a learner to follow) is the depth-first search animation. Figure 5 shows the major components of the depth-first search animation. The agent is represented by a small tank which starts at the opening of the maze, which is a node in the graph. In order to progress, the tank stops for a brief moment and randomly chooses an edge to follow (this is the visual indicator that a random action is being taken). Once that is decided, the tank travels across that edge, painting the line below it green, until it reaches the next node. The tank then repeats this process until one of three possible events occur: