He decides to think of the hut as a mathematical black box for the time being—that is, he’ll concentrate only on its inputs and outputs of information and ignore the internal details. Bletchley Park, taken in its entirety, is a black box of sorts: random letters stream into it, strategic intelligence streams out, and the internal particulars are of no interest to most of the people on the Ultra distribution list. The question that Waterhouse is here to figure out is: is there another vector of information coming out of this place, hidden subliminally in the teletype signals and the behaviors of the Allied commanders? And does it point to Rudolf von Hacklheber, Ph.D.?