Alan Turing's Notes Found After Being Used As Insulation At Bletchley Park

An anonymous reader writes: In 2013, a restoration project for Hut 6 of Bletchley Park uncovered a collection of papers being used as roof insulation. The papers were frozen to preserve them while they were inspected and repaired. Now they're on display at an exhibition showing items found during the restoration process. "The documents also included the only known examples of Banbury sheets, a technique devised by [Turing] to accelerate the process of decrypting Nazi messages. No other examples have ever been found. All the findings are unique as all documentary evidence from the codebreaking process was supposed to be destroyed under wartime security rules."