Logic Masters Deutschland e.V.

Click on the puzzle image to play!

Isn't it surprising that this simple puzzle geometry resolves with a logical solution path?

Rules: Normal Sudoku rules apply.

Parts of the grid are covered in fog. Placing the correct digits in row 9 and column 9 clears the fog.

Yin Yang in the fog: Shade some cells in the initial fog such that all shaded cells are orthogonally connected, all unshaded cells are orthogonally connected, and no 2x2 area is fully shaded or fully unshaded. Row 9 and column 9 are ignored regarding Yin-Yang rules.

A black-arrow cell contains the number of all shaded cells in arrow direction.

For n = 1,...,7, the digit in row n column 9 is one less than the digit in row 9 column n.

A red-arrow cell contains the sum of digits of all shaded cells in arrow direction; if a cell contains more than one red arrow, the condition must be fulfilled separately for each.

Your feedback, ratings and comments are highly appreciated. Have fun!

Background: In tomography, the shape of an object is recovered by observing projections on a reduced number of dimensions under various angles. This is particularly relevant in medicine where internal images of the body are obtained via computed tomography (CT).

4x4 Example: If you would like to explore the puzzle idea, you can start by solving the small puzzle below. Click on the image to play.