Nonogram

What are Nonograms?

Nonograms, also known as Picross, Paint by Numbers, or Griddlers, are picture logic puzzles in which cells in a grid must be colored or left blank according to numbers at the side of the grid to reveal a hidden picture.

In this puzzle type, the numbers are a form of discrete tomography that measures how many unbroken lines of filled-in squares there are in any given row or column. For example, a clue of "4 8 3" would mean there are sets of four, eight, and three filled squares, in that order, with at least one blank square between successive sets.

These puzzles are often black and white, describing a binary image, but they can also be colored. If colored, the number clues are also colored to indicate the color of the squares. Two differently colored numbers may or may not have a space in between them. For example, a black four followed by a red two could mean four black squares, some empty squares, and two red squares, or it could simply mean four black squares followed immediately by two red squares.

Strategies for Solving Nonograms

1. Start with the largest numbers: Rows or columns with large numbers or many numbers have less possible arrangements and are easier to solve first.
2. Look for overlaps: If a row or column has numbers that must overlap regardless of their exact position, you can fill in those cells immediately.
3. Use cross-referencing: Compare information from rows and columns to determine which cells must be filled or empty.
4. Mark empty cells: Keeping track of cells you know must be empty is just as important as marking filled cells.
5. Work iteratively: Solve what you can, then use that new information to solve more of the puzzle in subsequent passes.

With practice, you'll develop your own strategies and become more efficient at solving Nonograms. Challenge yourself with increasingly difficult puzzles to sharpen your skills!