Logic Masters Deutschland e.V.

Rules:

Normal Sudoku rules apply.

Digits separated by a white dot are consecutive. Digits separated by a black dot have a ratio of 2:1. Not all possible dots are necessarily given.

Draw a one-cell-wide loop of orthogonally connected cells. The loop may not touch itself, not even diagonally.

-- The loop must enter at least one cell of every given dot.

-- Oil-Water: Even digits on the loop are "oil", and odd digits on the loop are "water". Every horizontal loop segment is either all oil or all water. Oil floats on water, so for every vertical loop segment, even digits will always be in rows above odd digits. Note that if there are multiple loop segments in a row, that row may contain both even and odd loop digits.