Logic Masters Deutschland e.V.

Summation U-Bahn : Draw a loop network through the centers of some cells, which may branch or turn, but may not have any dead ends.

Assign each line shape (irrespective of rotation) a digit from 1 to 4 as follows: corner = 1, straight line = 2, branch = 3, cross = 4. Clues outside the grid indicate the sum of "digits" in each contiguous sequence of cells visited by the loop network, in the correct order. Consecutive sequences must be separated by at least one cell not visited by the loop network. For a given row or column, either all clues or no clues are given.

knapp-daneben : All clues are given off-by-one.

The puzzle is available online via penpa.