Puzzle guide
How to solve Mosaic
A Mosaic is a picture made of filled cells. Each number tells you how many cells are filled in the little square of nine around it, its own cell included. Read the numbers together and the picture appears, cell by cell.
The rules
- A number tells you how many cells are filled in its square of nine: its own cell and the eight around it.
- The number's own cell counts too. It can be filled as well.
- At the edge the square is smaller: six cells, or four in a corner.
- When every number is right, the filled cells show the picture.
A solved puzzle
Your first moves
- Find every 0: its whole square of nine is empty. Put an X on every cell.
- Find numbers as big as their square: a 9 in the middle, a 6 at the edge or a 4 in a corner. All of their cells are filled.
- Look for numbers that are already met: the rest of their square is empty.
- Then compare two numbers side by side. Their squares overlap, and the difference tells you a lot.
Techniques, step by step
Nothing or everything
The 4 in the corner has only four cells in its square, so all four are filled. The 0 at the edge has six cells, and none of them is filled: they all get an X. A 9 in the middle of the board, or a 6 against an edge, works the same way. These are the first cells to mark on any board.
A number that is met
The 3 already has three filled cells in its square of nine. It cannot have any more, so every other cell of its square stays empty, including the number's own cell. The opposite works too: if a number still needs as many filled cells as it has free ones, all of them are filled.
Two squares that overlap
The 6 and the 3 stand side by side, so their squares share six cells in the middle. The 3 can have at most 3 filled cells in that shared part. The 6 then needs at least 3 more, and its own left column has only three cells, so that column is completely filled. That leaves exactly 3 for the shared part, which already uses up the whole 3, so the 3's right column stays empty. This trick, comparing two neighbouring numbers, is the one every Mosaic is built around.
A number and all its neighbours
On hard boards, look at one number together with every number whose square touches it. Try the ways its free cells could be filled: some of them would leave a neighbour unable to reach its count, or push it over. Throw those away. A cell that is filled in every way that is left is filled, and a cell that is empty in all of them gets an X.
Common mistakes
- Forgetting the number's own cell. The square of nine includes the cell the number stands in. It can be filled too.
- Using nine cells at the edge. Against the edge of the board a square has six cells, in a corner only four.
- Counting like Minesweeper. Mosaic counts the number's own cell as well as its neighbours.
- Leaving free cells unmarked. Mark every cell you know stays empty with an X. Free cells are hard to tell apart from empty ones otherwise.
Questions and answers
Ready to play?
Start with nothing-or-everything, close finished numbers, and compare overlapping squares. The picture will show itself one cell at a time.