Four Sphinx Store Display Window Cards. [New York], 1936-37. Offset window cards advertising the sale of magic magazine The Sphinx, and featuring Paul Duke, Glen Pope, and two antiquarian conjuring prints, all as featured on the periodical?s cover. Used to sell subscriptions in magic shops of the era. 8 3/8 x 12 ??. Minor edgewear. Uncommon. Despite the popularity and relatively common nature of issues of The Sphinx ? the magazine is, almost unarguably the most significant and popular magic periodical of the twentieth century - these advertising cards are seldom encountered.