When you’multi-touch’ a single touch device it returns the midpoint between all of the contact points, so it would be pretty easy to fake. If you can use that data in a meaningful way, that’s all that matters. Just don’t expect the same kind of multifinger gestures on a. single touch resistive touch screen, pinches data is the mid point of your fingers, and the distance between your fingers gets longer equally from the. midpoint making detecting multiple fingers a moot point.”]
Source: https://gizmodo.com/multitouch-hacked-onto-nokia-5800-for-the-noble-purpose-5163368