Logic Masters Deutschland e.V.

Digits in cages cannot repeat and must sum up to zero. Digits on the indicated diagonals also sum up to zero, but may repeat if allowed by other rules.

Divide the grid into two orthogonally connected regions, such that no 2x2 area is entirely one region or the other. In one region, every digit counts as twice its value for the purposes of cages and diagonals. In the other region, every digit counts as the negative of its value for the purposes of cages and diagonals.[For example, a two-cell cage that adds up to zero could be fulfilled by a doubled 1 (which counts as 2) and a negated 2 (which counts as -2).]

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