What is Mosaic?
Mosaic is a picture-forming logic puzzle, also known as Fill-a-Pix, Nurie, Count and Darken, Mosaico and Voisimage. The grid contains number clues, and the finished answer is a pattern of dark and light cells.
Each number tells you how many cells are dark in the 3x3 neighbourhood around that clue. The clue cell itself counts too, so a 9 in the middle fills all nine surrounding cells, while a 0 clears them all.
- Fill cells dark or mark them light.
- Every clue counts the clue cell plus its touching neighbours, including diagonals.
- Corner clues count four cells, edge clues count six cells and centre clues count nine cells.
- The goal is to satisfy every clue and reveal the hidden mosaic picture.
- The puzzles on this page are checked for a single solution before play begins.
How to play Mosaic online
Click or tap a square to cycle it between unknown, dark and light. On a mouse, right click cycles backwards, which makes it quick to mark cells you know cannot be dark.
Use Check when you want feedback without seeing the full answer. Hint fixes one useful cell from the unique solution, and Solution reveals the complete image if you want to study the logic.
- Start with 0 clues because every cell in that neighbourhood must be light.
- Use maximum clues next: 4 in a corner, 6 on an edge and 9 in the middle.
- Compare overlapping clues that share most of the same cells.
- When a clue already has enough dark cells, mark the rest of its neighbourhood light.
- When the remaining unknown cells must all be dark, fill them together.
Mosaic grid sizes and difficulty
Smaller Mosaic grids are friendly because you can see every neighbourhood at a glance. Larger grids create longer chains of overlapping clues, so one forced mark can unlock a much bigger part of the picture.
Easy puzzles keep more clues visible and include more direct 0, edge-maximum and centre-maximum deductions. Medium puzzles remove more clues. Hard puzzles use fewer clues and ask you to compare several nearby neighbourhoods before a cell becomes forced.
- 6x6 Mosaic is the best starting size.
- 8x8 Mosaic gives a balanced online puzzle.
- 10x10 Mosaic creates a larger picture and more layered deduction.
- Easy, medium and hard change clue density and solving pressure.
- Every new puzzle is generated from a checked single-solution clue set.
Mosaic strategy tips
The strongest Mosaic strategy is to count what a clue can still see. If a clue already has the required number of dark cells, every other unknown cell around it is light. If the clue needs exactly as many dark cells as there are unknowns left, fill all of them.
Overlaps are where Mosaic becomes satisfying. Two adjacent clues often share six cells. If their numbers differ by one, the non-shared cells usually carry the important information.
- Scan for 0, 4, 6 and 9 clues first.
- Keep light marks visible; they are just as important as dark cells.
- Compare neighbouring clues instead of solving each number in isolation.
- Recount completed clues after every forced move.
- Use the edge of the grid to remember that corner and side clues have smaller neighbourhoods.
Why unique Mosaic puzzles matter
A good online Mosaic puzzle should not ask you to guess between two possible pictures. If two different dark-and-light patterns satisfy the same clues, the solving path becomes uncertain.
This game counts solutions during generation and only accepts a board when the clue set has exactly one answer. That makes Check, Hint and Solution point to the same intended Mosaic.