A mop of light brown hair shakes as a slender nine-year-old boy named Jack bangs furiously at his keyboard. Jack's eyes are fixed on a clock with six hands, which denote the month, day, hour, minute, second and 60th of a second. As soon as he types 10:28:2:14:56:32, a new clock appears, and he hammers out another set of numbers. An affable 14-year-old student named Marti had just taught me the exercise, and I guessed I could have solved one of these clocks in a few minutes. Jack was finishing one every seven seconds.