Students crowd around, giggling and waiting for their phone clocks to hit precisely 10:28 AM. Their classroom door has been labeled as “Bletchley Park,” and is marked with strict instructions to knock at exactly 10:28, and to not be early nor late. With three knocks, the door swings open, and they are greeted not by Commander Alastair Denniston. As they enter, they are transported back in time to 1941, and spend the next hour racing the clock as Alan Turing,...