"From a single such detonation, yes," said the visitor. "Now, Mr. Dyson, or any other physicist who made it out of his sophomore year, would have known about constructive interference—the phenomenon where two wave crests, meeting at a given place and time, will sum to produce a much higher crest. That much is old hat in the world of mathematical physics. But what is different now, as compared to 1962, is that we have computers. Precision guidance systems. Split-second timing and communication technology. So. Our whole mentality around weapon design has changed. In Dyson’s day, a Cold War military planner might have used a nuclear weapon to take out a whole city, just to destroy a single factory. Overkill, to be sure, but the best they could manage with unguided ballistic warheads. Today we would use a cruise missile that would strike a key component of that factory—say, a power transformer or a meeting of senior management—with a precision measured not in meters but centimeters. Much cleaner, much less collateral damage, much cheaper. Likewise, a modern approach to Dyson’s 1962 scenario would be to get rid of the nukes straightaway and stick with those containers full of H.E. Drop those in precisely known locations not far from the target. Detonate them in a precisely timed sequence. The individual waves from any one detonation don’t amount to much. By the way, that’s a feature, not a bug. During a storm they aren’t even detectable. They don’t rise above the noise floor. But if you’ve set it all up right, there is one and only one location where all those waves sum together and create what seems to be a rogue wave, enormously bigger than all the others. If it just happens to cave in the Maeslantkering, why, the North Sea then rushes in and does your work for you."