How to play Mosaic

Shade squares so that every number equals the count of shaded squares in the 3×3 block around it. Also known as Picture count puzzle, 3×3 shading.

▶ Play Mosaic ⊞ Open the solver

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.

Playing Mosaic on Puzzle Solvers

Choose pictures or random patterns, a size and a difficulty, then press New Puzzle.
Tap a square to shade it, again for a white dot, again to clear. Drag to paint many.
Point at a number to outline its 3×3 block; finished numbers fade so you can see what’s left.
When you finish, the picture appears in colour. Hint explains the next deduction.

Open the Mosaic game →

Using the Mosaic 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.

Open the solver →

A worked example

A 0 sits next to a 6. The 0 makes six squares white — all shared with the 6’s block.

The 6 has only three other squares left, but needs six shaded… so look again: the 6 must sit further away. When the 6’s unknown squares equal its need, shade them all.

Strategies

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.
Work outwards. Each finished area gives new information to the numbers around it.

Common mistakes

Forgetting that the number’s own square counts.
Counting a 3×3 block at the edge as if it were full size.
Shading by guesswork instead of from a number.

Where it comes from

Grid puzzles where numbers count the shaded squares around them are close cousins of picture logic puzzles and became popular in puzzle magazines in the 2000s.

Frequently asked 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.

Keep going

All guides: How to play every puzzle and game.