DOUBLE BOX PREDICTION CHEST. Indiana: Harry Roydon, 1960s. A prediction of future events is proven to be accurate when two nested boxes are unlocked and the billet bearing the prognostication is removed from the innermost of the two wooden chests. Requires no special keys or tables. Larger box 8 ? x 7 ? x 6 ??. With padlocks and instructions. Uncommon. Harry Roydon is best-known for the clever yet simple pocket tricks he invented, though several of his stage props, such as this prediction effect are equally devious. While his close-up tricks are relatively common (and some of them, such as the Crazy Cube, have become standard beginner tricks), his parlor apparatus is relatively scarce.