griddlers

Griddlers, also known as nonograms, picross, or paint-by-numbers puzzles, are picture logic puzzles played on a grid. Each row and column has a sequence of numbers that specify the lengths of groups of filled cells in that line. The numbers must be separated by at least one empty cell; the grid can be monochrome or colored. Solving involves logical deduction rather than guessing, gradually revealing a hidden image as cells are shaded or left blank. Common techniques include line scanning to determine where blocks must appear, overlapping analysis of sequences, and cross-checking between rows and columns. Some puzzles mark cells as definitely filled or empty, helping propagate constraints.

Griddlers come in many sizes, from small 5x5 samples to large 25x25 or bigger; colored variants use multiple colors with separate sequences per color. There are also irregular or symmetrical designs, and online and print collections.

History: The puzzle originated in Japan in the 1980s and was popularized internationally through Puzzle Communication Nikoli, where it is typically called Nonograms. The term griddlers is used by various publishers and games to refer to similar picture logic puzzles, sometimes specifically those with larger grids or a distinct solving approach. They appear in newspapers, puzzle books, apps, and online puzzle sites, appealing to solvers who enjoy deductive reasoning and image construction.