In November 1941, advertisements for a new board game called The Deadly Double appeared in American magazines. These ads later drew suspicion for possibly containing coded messages, for unknown agents, giving advance notice of the Pearl Harbor attack. The ads were headlined "Achtung, Warning, Alerte!" and showed an air raid shelter and a pair of white and black dice which, despite being six-sided, carried the figures 12, 24, and XX, and 5, 7, and 0, respectively. It was suggested that these could possibly be interpreted as giving warning of an air raid on day "7" of month "12" at approximate latitude coordinate "20" (Roman numeral "XX"). The board game was an actual product with sets sold during this time.
