What is a Nonogram?
A Nonogram hides a simple black-and-white picture behind a blank grid. Instead of a picture reference, you get a set of numbers next to every row and column. Each number is one unbroken run of filled cells in that line, listed in order, and there's always at least one empty cell between runs. Work out where those runs have to sit, row by row and column by column, and the picture appears cell by cell.
The format goes by a few names depending on where you first ran into it. Nintendo's handheld games popularized it as Picross, short for picture crossword, while puzzle books and magazines often print the same thing under the name Griddlers. Nonogram is simply the more general term, and the rules don't change no matter which label is on the page.
Every puzzle on this page is generated and then checked before it's ever shown to you. A line solver works through the clues the same way a person would, resolving whichever rows and columns it can and feeding that information back into the rest of the grid, over and over, until either the whole picture falls out or it doesn't. Only puzzles where the whole grid resolves on its own get served, which means the solution is unique and there's always a path to it that never requires a guess.
Three sizes are on offer. The 5x5 board is a two-minute puzzle, good for a quick break. The 10x10 sits in the middle, big enough for a real picture to take shape without dragging on. The 15x15 is the long game, with enough rows and columns that the every-five gridlines genuinely earn their keep.
