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Though the trick is reported to be of oriental origin, Frank Ducrot is the inventor of the common method using a clear disk. He published his version in Mahatma, Vol. 4 No. 9, Mar. 1901, p. 454. Ducrot admits in the write-up that the basic trick already exists and is “ever popular.” Al Baker improved the method with a rubber cover in his marketed, “Chinese Rice Bowls,” 1933. Alexander Herrmann invented the double-walled “Brahman Bowls.”