The phone mostly..... The one mobile game which I have poured a lot of time into is Real Racing 3. Tilting the phone like a steering wheel for analogue driving

The phone mostly..... The one mobile game which I have poured a lot of time into is Real Racing 3. Tilting the phone like a steering wheel for analogue driving input is awesome. Combine that with head tracking to allow analogue acceleration and breaking control by tilting the phone forwards and backwards would be excellent. On the other axis I can image controlling the view point slightly to allow looking to your left and right, even just checking wing mirrors. And those thoughts are just about a game which already exists. I can also start to dream about game mechanics which haven't been possible until head tracking......