"one stubborn glitch they couldn't figure out: the program did a wonderful job spewing out data on the trajectory of artillery shells, but it just didn't know when to stop. Even after the shell would have hit the ground, the program kept calculating its trajectory, "like a hypothetical shell burrowing through the ground at the same rate it had traveled through the air," as Jennings described it. "Unless we solved that problem, we knew the demonstration would be a dud, and the ENIAC's inventors and engineers would be embarrassed."69 Jennings and Snyder worked late into the evening before the press briefing trying to fix it, but they couldn't. They finally gave up at midnight, when Snyder needed to catch the last train to her suburban apartment. But after she went to bed, Snyder figured it out: "I woke up in the middle of the night thinking what that error was. . . . I came in, made a special trip on the early train that morning to look at a certain wire." The problem was that there was a setting at the end of a "do loop" that was one digit off. She flipped the requisite switch and the glitch was fixed. "Betty could do more logical reasoning while she was asleep than most people can do awake," Jennings later marveled. "While she slept, her subconscious untangled the knot that her conscious mind had been unable to."