Another prank involved a pocket device Wozniak built that could emit TV signals. He would take it to a room where a group of people were watching TV, such as in a dorm, and secretly press the button so that the screen would get fuzzy with static. When someone got up and whacked the set, Wozniak would let go of the button and the picture would clear up. Once he had the unsuspecting viewers hopping up and down at his will, he would make things harder. He would keep the picture fuzzy until someone touched the antenna. Eventually he would make people think they had to hold the antenna while standing on one foot or touching the top of the set. Years later, at a keynote presentation where he was having his own trouble getting a video to work, Jobs broke from his script and recounted the fun they had with the device. "Woz would have it in his pocket and we’d go into a dorm, where a bunch of folks would be, like, watching Star Trek, and he'd screw up the TV, and someone would go up to fix it, and just as they had the foot off the ground he would turn it back on, and as they put their foot back on the ground he'd screw it up again." Contorting himself into a pretzel onstage, Jobs concluded to great laughter, "And within five minutes he would have someone like this."