Matchstick puzzle
Matchstick puzzles are rearrangement puzzles in which a number of matchsticks are arranged into shapes or numbers, and the problem to solve is usually formulated as moving a fixed number of matchsticks to achieve some specific other arrangement.
The puzzles may ask the solver to alter some mathematical equation,[1] often with numbers represented as Roman numerals, or Arabic numerals in a seven-segment display typeface. Other puzzles challenge the solver to rearrange a crude matchstick picture.[2]
Some matchstick puzzles require lateral thinking, such as changing a number into a mathematical symbol.[3]
Puzzles may also be set with no starting position, simply challenging the solver to create an arrangement using a number of matches. One example that requires lateral thinking is to form four equilateral triangles from six matches; this can only be done by arranging the matches in a three-dimensional pyramid shape.[4]