Mechanical Puzzle

A classic sliding puzzle: fifteen numbered tiles and one blank in a 4×4 frame; slide tiles into the blank until they read 1–15 in order.

A mechanical puzzle of linked rings on a handled bar: following two simple rules, take the rings off one by one, or put them back on. The classic nine-ring set takes hundreds of moves.

A sliding block puzzle on a 4×5 board: shuffle blocks of different sizes to get the 2×2 big block out through the bottom exit. Known in China as Huarong Dao and in Japan as Hakoiri Musume.

Press a light to toggle it and its four neighbors; the goal is to turn every light off. The classic board is 5×5.

A 3D interlocking wood (burr) puzzle: notched sticks assemble into a rigid cross without glue; take apart and reassemble.

A two-player code-breaking game: guess a hidden row of colored pegs; black keys mark right color and place, white keys mark right color wrong place.

A dodecahedral twisty puzzle: turn the twelve pentagonal faces until each face is a solid color. Six- or twelve-color schemes are common.

A one-player pegboard puzzle: jump a peg horizontally or vertically over a neighbor into an empty hole and remove the jumped peg, usually until only one peg remains.

A tetrahedral twisty puzzle: turn layers about the four vertices until each triangular face is a solid color.

A 3D twisty puzzle: turn the layers of a 3×3×3 cube until each face is a solid color.

A 6×6 traffic sliding puzzle: slide cars and trucks along their lanes to free the red car through the exit.

A cube-shaped twisty puzzle that turns about its corners, moving half the cube at a time, until all six faces are solid colors.

Fold a chain of 27 linked small cubes, section by section, into a solid 3×3×3 cube.

A shape-shifting twisty puzzle: turn the top and bottom layers, flip the middle, and restore both the cube shape and its colors.

Move a size-ordered stack of disks between three pegs without placing a larger disk on a smaller one.