ARf is our first experiment with creating an AR game on the iPhone. Play with a virtual puppy on your desk: use the touch screen to tell him where to go, or to poke and pet him! Build up a world with multiple markers so he has room to run. Give him a water bowl or a friend to play with. ARf is currently just an experiment to explore some of what’s possible with such a device, but it clearly has a lot of room to grow. As we make the system more functional, we would like to add more elaborate Pet AI and explore multiplayer interactions, so friends can play with their pets together on the same desk, or in distributed locations while sharing a common virtual space.