The hardest part was trying to make Curiosity’s dialog feel natural. Ideally, if I had more time, I would want to implement Google’s Natural Language Processing API. Because I was not able to include that this time, I had to essentially try to cover a lot of potential questions by building it into the code. The wizard of oz and user testing sessions were helpful because I was able to see what kinds of questions people would want to ask the Rover. Most of the time, they were scientific questions like “how big is Mars?” but once the user learned more about the personality of Curiosity, they would start asking questions that were more related to him, such as “what’s your favorite thing to do” or “who from Earth would you want to join you?”.