Logic Masters Deutschland e.V.

Happy New Year! Here is a pack of three small Chaos Constructions to kick off 2026, and on the harder side for their size – maybe not quite as thorny as this one, but one never knows.

Unlike the usual outside 2x3 to fill in the digits missing per box or region, you will find for those a left-side strip to enter the digits per region, where each cell is aligned with the zero of that region. This strip needs to be empty for the solution check to trigger, but you might find it useful for the solve and/or the solution code.

RULES

CHAOS CONSTRUCTION
– For each grid, divide the grid into 6 regions, each made of 6 orthogonally connected cells. The regions and the grid as a whole must follow the Doppelganger rules as described below.
[Duck Soup only]
– The digit in the top left cell of a region (ie, its leftmost cell in its highest row) is its region number. All region numbers must be different, and together they must form a set of the digits 1 to 6.

DOPPELGANGER
– Every row, column, and region contains the digit 0 always, as well as five out of the six digits from 1 to 6 (ie, it's missing one digit that is not 0).
– 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, its column, and its box must be three different digits, yet zeros always have a null value (ie, zero).

RENBANS & GERMAN WHISPERS
– Each purple line must contain a series of consecutive, non-repeating digits, which can appear in any order.
– Adjacent digits along a green line must differ by at least 5.
[Duck Soup and Sawtooth only]
– Regardless of the type of line, the two ends of each line must belong to the same region.
[Travellers only]
– The digit in a dot is exactly 1 less than the number of different regions that its Renban line travels through. No two dots may contain the same digit.