Logic Masters Deutschland e.V.

Lines cross but never branch.

Entropic Lines: Along beige lines any group of three consecutive cells contain one low {1,2,3}, one medium {4,5,6}, and one high {7,8,9} digit.

Modular Lines: Along teal lines any group of three consecutive cells contain digits with different remainders under division by 3. (i.e. one of {1,4,7}, one of {2,5,8}, and one of {3,6,9}.)

Equal Sum Lines: The digits along each of the three gray lines have the same sum.

f-puzzles: https://f-puzzles.com/?id=2l6ykuw4
CTC: https://tinyurl.com/pbxbfyfw