This app is based upon a telepathy test that the Official Prisoner Appreciation Society commissioned us to design back in 2008. In the episode of The Prisoner
entitled "The Schizoid Man," actor Patrick McGoohan uses a special deck of symbol cards to test Extra Sensory Perception. That deck is similar but not identical to the Zener cards made famous by parapsychologist J. B. Rhine in the 1930s. We created an exact replica of the prop deck to the delight of the Society, but as fate had it the cards never went into print.