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.

A matchstick puzzle ("Move 1 matchstick to make the equation 6+4=4 valid") and its solution below

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]