Logic Masters Deutschland e.V.

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This is my response to Scojo's setting prompt a few weeks ago as redeemed by aqjhs, which was to make a puzzle in which zero features prominently. My initial idea was to play around with modularity, but after aqjhs made me aware of the Doppelgänger ruleset, which I didn't realise until now has already been expertly showcased by setters such as Kafkapharnaum and bodemeister, I couldn't resist trying it out myself. My dad and I explored an idea and took it in slightly different directions, resulting in surprisingly contrasting solution paths. Many thanks to aqjhs for testing both.


Toroidal Chaos Construction
• Divide the main 6x6 grid into six 6-cell regions, which may wrap around the grid toroidally, e.g. r1c1 may orthogonally connect to r1c6, r6c1, r1c2 and r2c1;
• Some region borders have been given.

Doppelgänger
• Fill each cell of the main grid such that every row, column and region contains a 0 and five different digits from 1-6;
• No two rows, no two columns and no two regions may be missing the same digit;
• For each 0 in the grid, the digits missing in its row, column and region must be three different digits.

Zero Sum Lines
• Values on a hollow grey line, which may repeat, sum to zero;
• For the purpose of this sum, the value of a 0 is minus one (-1) multiplied by the sum of the digits missing in its row, column and box.

(Cells outside the main 6x6 grid can be used to record missing digits and do not affect solution check)

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Try Shifty, a 4x4 puzzle acting as practice for both puzzles.

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