Mosaic Solver

Mosaic Solver — Step by Step

Choose the size, click a square and type its number (0–9). Leave blank squares empty. Then press Solve. Or play a generated puzzle and send it here with one click.

Mosaic Solver: rules, how to use it, tips

Shade squares so that every number equals the count of shaded squares in the 3×3 block around it.

The rules

Each number looks at the 3×3 block centred on its square, including itself (smaller at the edges and corners).
The number is how many of those squares are shaded.
Squares without numbers can be shaded or not — the numbers decide.
Shading every square correctly reveals the picture.

Using the solver

Type the numbers of your puzzle (or press Sample).
Press Solve and step through: 0s and full blocks, counts that are complete, overlapping blocks and what-ifs.

Tips

0 and 9. A 0 leaves its whole block white; a 9 shades all nine squares. In a corner, a 4 shades all four.
Complete counts. When a number already has its count shaded, the rest of its block is white.
Exactly enough room. When a number’s unknown squares are exactly what it still needs, shade them all.
Overlaps. Two neighbouring numbers share six squares. The difference between them tells you about the squares only one of them sees.

The full guide, with a worked example and common mistakes: How to play Mosaic.

Questions

Where do the pictures come from?

They are adapted from the open Twemoji emoji set (CC BY 4.0) — the credit is on this page.

Is there always one answer?

Yes — every puzzle here is checked to have exactly one solution.

What’s the difference from a nonogram?

Nonogram clues are outside the grid and describe whole rows and columns; Mosaic clues are inside and count only their neighbours.

How do I solve one from a book?

Open the Mosaic Solver, type the numbers and press Solve.