Logic Masters Deutschland e.V.

The following puzzle is way different from my usual outputs over here... and yes, I'm finally back to more venture with other pencil puzzles and their hybrids.


Honestly, the current Sudoku world has been so saturated and it's rather rough to witness some of the passionate projects from myself and also from others being overshadowed.
Despite not having my best mentality for this in real life, I still volunteered to revisit a lot of older puzzles for better inspirations and also to test my ability to try things that are rather out of my comfort zone. Funny enough, revisiting bunch of older so-called U-bahn (Underground) puzzles started to hit my soft feeling and then ultimately, this on-going puzzle series from Agent gave me a cool opening idea for an U-bahn puzzle...


And so here it goes: my first ever attempt to set an U-bahn puzzle - which is directly inspired by that series.
Special thanks to Agent for testing this one as well! :)

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I shall consider this as my prep for more exciting pencil puzzle projects in the near future and I hope that I can deliver my best for all of them too :)
Rules:

- Draw a loop network through the centers of some cells in the main grid, which may branch or turn, but cannot have any dead end.

- For each cell belong to the loop network, assign its line shape (irrespective of rotation) a 'digit' from 1 to 4 as follows:
corner = 1, straight line = 2, branch = 3, cross = 4.

- Each set of clue[s] given outside a row/column shows the sum of 'digits' in their respective contiguous sequence[s] of cells visited by the loop network, in the correct order. If the set has more than one clue then any two consecutive sequences must be separated by at least one cell not visited by the loop network.

- A question mark clue (?) represents any digit in the range of 1-9 (i.e non-zero single digit sum).

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Setter's note: For those that aren't really familiar with how the concept works, here's an example image below. This example puzzle can also be solved in either Penpa plus or Sudokupad.

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Puzzle:   Penpa plus  -  Sudokupad


The answer check in penpa link will activate once the whole loop network is correctly drawn. For now, good luck and have fun solving!