Rules are simple:
- Each tile must be either white or black.
- Numbers before each row/column tell how many black tiles are in that row/column.
- Each tile must contain an integer between and the size (width and height) of the grid.
- In each row and column there must be no two black tiles with the same number.
- Each number must be on a domino (a domino is a rectangle containing two adjacent numbers). Dominos can be either vertical or horizontal. Each domino must contain exactly two numbers and dominos must not overlap.
- Each domino must contain at least one white tile.
At the image on the right we can see an example of an unsolved Yume puzzle. Gray tiles mean that we do not know yet whether they are white or black. We can see that some numbers are given, while some numbers (two of them) are missing.
A good Yume puzzle should have exactly one solution. The puzzle from the example above can be solved in exactly one way and the solution can be seen at the image on the right.