Spatial Reasoning

A Nikoli logic puzzle: place bulbs so every white cell is lit, no bulbs shine on each other, and numbered walls have the required adjacent bulbs.

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.

Pack six flat pieces of 2 to 7 cubes into a solid 3×3×3 cube; there are about 13 distinct solutions.

An inequality puzzle: fill an n×n grid with 1–n so no digit repeats in any row or column, and every > or < sign between neighbors holds.

A bridge puzzle: connect numbered islands with horizontal or vertical bridges so each island has as many bridges as its number. Two islands share at most two bridges, bridges never cross, and all islands must link up.

Fit irregular, usually interlocking pieces together to rebuild a complete picture and outline.

An arithmetic puzzle: fill an n×n grid with 1–n so no digit repeats in any row or column, and the numbers in each thick cage reach its target with the given +, −, ×, or ÷.

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.

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

A pearl loop puzzle: draw one simple loop through cell centers that visits every white and black circle, obeying straight/turn rules that differ by color.

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

A picture logic puzzle: paint cells filled or blank so every row and column's contiguous blocks match the edge run-length clues—often revealing a hidden image.

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.

Fit the twelve pentominoes, each made of five joined squares, into a rectangle such as 6×10 or a given shape, with no gaps.

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 Japanese seven-piece silhouette puzzle that cuts a square differently from the Chinese Tangram; all seven pieces are used without overlap to match a target outline.