Crooked Paintball

With some skill, curved shots around obstacles are already feasible, by shooting the ball very tightly along the obstacle. Aerodynamics will bend the flight path around, some.

This idea uses spin of the ball to achieve similar effects : Inside the barrel are three stripes of piezo material, that can change their roughness according to the voltage applied: one every 120°. The thumb of the shooter rests on a (this is a possibly not PC term, please correct me if that is the case) coolie-hat, with which he can determine the extent to which he wishes the flight path to be altered, and in which direction. This is translated into different voltages being applied to the in-barrel stripes, who change their roughness accordingly, giving spin of a detemined magnitude around a detemined axis, to the ball.