This is a paper ring with a number puzzle. The hint is actually the logo that is at the beginning (which of course will be right after the end when it's a ring).
A card (roughly the size of an index card) with an image that contains 54 playing cards (some duplicates, of course!). A spectator chooses one of the playing cards and, after a few questions, the magician reveals the choice!
Are there any polycubes that can be unfolded into exactly a rectangle? This problem was solved in 2019. The smallest solution forms a nice puzzle — fold the rectangle into a polycube!
The puzzle is to fit 14 “rabbiduck” polyomino pieces into an 8x11 rectangle. (Gardner wrote about polyominoes in multiple columns. The specific polyomino pieces used are inspired by the rabbit/duck illusion that Gardner called the Rabbitduck in his…