In Jedi Trainer a drone is flying around a Jedi knight trainee aiming at training its ability in using the light saber, as in the first episode of the Star wars saga with Luke Skywalker.
By analyzing the image from the onboard camera, the drone maintains the distance from the player, keeping it always in the image, and moving slightly left and right as to look for the best position to shot. When appropriate, it makes a sound with its propeller, simulating a laser shot, and the player has to parry it by putting the light saber in front of her/his chest.
The drone is intrinsically adapting to the style of movement of the player: a more active player will have to face a more active trainer.