1. A method for interaction with a computer, the method comprising: receiving, by a computer, a sequence of three-dimensional maps containing at least an arm, including an elbow and a hand, of a user of the computer; identifying, in the maps, a controlled device that is coupled to the computer; analyzing the maps to detect a gesture performed by the arm toward the controlled device; and actuating the controlled device responsively to the gesture on condition that the elbow is extended in the gesture at an angle no less than a predefined angular threshold.