A nonogram generator that builds genuine, logic-solvable grid puzzles — the kind known as Picross, Hanjie, Griddler, or paint-by-numbers — then lets you solve them on screen and print them with a matching answer key. Pick a size and difficulty, and the tool produces a fresh puzzle whose row and column number clues can be worked out by pure deduction, with exactly one correct solution. It is built for puzzle fans, teachers assembling printable worksheets, parents keeping kids busy on a long trip, and anyone who wants a quick logic workout without an app or an account.
How it works
A nonogram hides a pattern inside a grid. The numbers beside each row and above each column describe the lengths of the consecutive runs of filled cells in that line, in order, separated by at least one empty cell. Your job is to figure out which cells are filled using only those clues.
This generator works in three stages. First it builds a random grid, filling each cell with a probability set by the difficulty you chose. Then it derives the clues by scanning every row and column and recording the run lengths. Finally — and this is the important part — it runs a logical line solver: for each line it computes which cells are forced to be filled or empty across every arrangement that fits the clue, then repeats across rows and columns until nothing more can be deduced. A puzzle is only accepted if that deduction completely solves the grid and reproduces the original layout exactly. That single test guarantees two things at once — the puzzle never requires guessing, and its solution is unique. Any candidate that fails is thrown away and a new one is generated, so you always get a fair puzzle.
On screen you solve directly on the grid: left-click fills a cell, and right-click marks a cell you have ruled out with an X — exactly the two-state workflow experienced solvers use on paper. The board signals the instant every row and column matches its clues. Bold guide lines every fifth row and column keep large grids readable.
Example
Suppose you generate a 5×5 easy puzzle. A row clue of 2 1 means that row, read
left to right, has a run of two filled cells, then at least one empty cell, then
a single filled cell. If the column clues for that area force the first cell to
be empty, you can immediately slide the run of two to start at column two,
filling cells two and three, leaving a gap, and placing the lone cell — often
without even looking at the rest of the grid. String enough of these forced
moves together and the whole picture resolves.
When you export, the PDF has two pages: a clean empty puzzle to solve with a pencil, and a separate answer key with the solution shaded in. Both pages print the size, difficulty, and seed so a set of printouts stays organised. Every puzzle, clue, and export is produced in your browser — nothing is uploaded.