By fourth grade Wozniak became, as he put it, one of the "electronics kids." He had an easier time making eye contact with a transistor than with a girl, and he developed the chunky and stooped look of a guy who spends most of his time hunched over circuit boards. At the same age when Jobs was puzzling over a carbon microphone that his dad couldn't explain, Wozniak was using transistors to build an intercom system featuring amplifiers, relays, lights, and buzzers that connected the kids' bedrooms of six houses in the neighborhood. And at an age when Jobs was building Heathkits, Wozniak was assembling a transmitter and receiver from Hallicrafters, the most sophisticated radios available. Woz spent a lot of time at home reading his father's electronics journals, and he became enthralled by stories about new computers, such as the powerful ENIAC. Because Boolean algebra came naturally to him, he marveled at how simple, rather than complex, the computers were. In eighth grade he built a calculator that included 100 transistors, 200 diodes, and 200 resistors on ten circuit boards. It won top prize in a local contest run by the Air Force, even though the competitors included students through 12th grade.