Woz became more of a loner when the boys his age began going out with girls and partying, endeavors that he found far more complex than designing circuits. "Where before I was popular and riding bikes and everything, suddenly I was socially shut out," he recalled. "It seemed like nobody spoke to me for the longest time." He found an outlet by playing juvenile pranks. In 12th grade he built an electronic metronome, one of those tick-tick-tick devices that keep time in music class, and realized it sounded like a bomb. So he took the labels off some big batteries, taped them together, and put it in a school locker; he rigged it to start ticking faster when the locker opened. Later that day he got called to the principal's office. He thought it was because he had won, yet again, the school's top math prize. Instead he was confronted by the police. The principal had been summoned when the device was found, bravely ran onto the football field clutching it to his chest, and pulled the wires off. Woz tried and failed to suppress his laughter. He actually got sent to the juvenile detention center, where he spent the night. It was a memorable experience. He taught the other prisoners how to disconnect the wires leading to the ceiling fans and connect them to the bars so people got shocked when touching them.