This puzzle gives pseudocode instructions for the little marker in the lower left corner. The program has been translated into Snap! Programming here, albeit with a couple shortcuts to avoid the “WHILE tile has not been visited before” logic. To view it properly, click on the stop button in the upper right corner, followed by the two arrows in the top middle, and finally the two footprints to the left of that. Now if you click the green flag, the program will start again, activating step-by-step.
Importantly, this implementation leaves a green dot on each tile it visits. When the program reaches its final loop, the visited tiles spell out the answer, BOT.
It is not significantly more difficult to solve this puzzle by hand, though it will take a good deal more time.