Lights Out is an electronic game released by Tiger Electronics in 1995. The game consists of a 5 by 5 grid of lights. When the game starts, a random number or a stored pattern of these lights is switched on. Pressing any of the lights will toggle it and the adjacent lights. The goal of the puzzle is to switch all the lights off, preferably in as few button presses as possible.
Merlin, a similar electronic game, was released by Parker Brothers in the 1970s with similar rules on a 3 by 3 grid. Another similar game was produced by Vulcan Electronics in 1983 under the name XL-25. Tiger Toys also produced a cartridge version of Lights Out for its Game com handheld game console in 1997, shipped free with the console.
A number of new puzzles similar to Lights Out have been released, such as Lights Out 2000 (5×5 with multiple colors), Lights Out Cube (six 3×3 faces with effects across edges), and Lights Out Deluxe (6×6).