Logic Masters Deutschland e.V.

• Standard sudoku rules apply: The digits 1 through 9 appear in every row, column, and box.
• Skyscrapers: Each cell in the grid represents a ‘skyscraper’ whose height is the digit in that cell. Taller skyscrapers obscure the view of smaller ones. Digits outside the grid tell how many skyscrapers are visible looking across the row or column from the direction of the clue.
• Zipper Lines: On lavender zipper lines, pairs of digits equidistant from the center of the line sum to the central digit on the line. R9C5 is the center of two crossing zipper lines.

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