Logic Puzzles

9. The Folded Sheet Challenge

The puzzle (Dudeney's "Folded Sheet")

Take a rectangular sheet and rule it into eight squares — two rows of four. Number the squares on one side only, in the odd order shown below. The paper is uncut; all ten interior lines are creases.

Now fold the whole sheet down into a single square packet, one square in size and eight layers thick, so that the numbers run in order from the top: 1, 2, 3, 4, 5, 6, 7, 8 — with the "1" face up on top and every other square beneath it.

For context, the text notes there are 40 distinct ways to fold this sheet into a packet with 1 face up on top; only one of those 40 gives serial order. The second arrangement is the same challenge with the numbers scrambled differently, and is much harder.

Added 1 September 2026 · Updated 1 September 2026