Sony has recently filed a number of patents related to haptic feedback via friction, instead of the vibration method that most devices use. A "rolling contact ball gripping mechanism" on the end of a stylus uses actuators to increase or decrease the ball's resistance to rolling, making it easier or harder to move the stylus across a screen.
The brace of patents for haptic peripherals all appear to use the same general idea for an interface but give different examples on how it can be used, notes Engadget. It could be used to demonstrate how "fatigued or damaged" a character in a game is, or for "carving and molding" objects in a 3D modelling application, or quite simply to simulate the feel of writing or drawing on paper more accurately.
Though such a system has its benefits, it does have down sides as well, the biggest issue of which being cost. Such a stylus would be far more expensive than those already on the market, forcing people to think about whether getting such an item is really worth doing.