While Dr. Sawa's coin production using the plot of a human slot-machine (Genii, Vol. 41 No. 1, Jan. 1977, p. 23) is the best-known use of this presentational gimmick, the plot was first used by L. L. Ireland (apparently accompanying a marketed item called “The Fifty Cent Trick”, which came with a penny holder). The Ireland trick is described in the final paragraph of Paul Studham's “The Human Slot Machine” in Bull's-Eye Coin Tricks by L. L. Ireland and Ed Marlo, 1942, p. 24. In the Ireland trick, the performer uses a spectator as a slot machine, dropping a coin into his breast pocket, pulling down his arm and then producing a handful of pennies from under his vest, stolen from a coin holder. The Studham trick reversed the roles: Someone dropped a coin into the performer's breast pocket and pulled down his arm, upon which the performer pulled a drink from under his own vest. Hans Trixer later published an effect using the presentational idea in The Gen: “Slot Machine Trick”, Vol. 8 No. 8, Dec. 1952, p. 235. This is a bit closer to Sawa's effect. Two coins are apparently inserted into the performer's fist and changed into a miniature bottle of Coke or liquor. While presented as a slot machine, this seems more like a vending machine.