Normal Sudoku rules apply.
Each box in the grid has a height value equal to 10 times its center digit. Each cell in the grid has a height value equal to its digit + its boxes’ height.
A river system, represented by the blue lines, flows throughout the grid. After visiting a cell, the river continues downhill to the orthogonal or diagonal neighbour with the lowest height value. If none of the neighbouring cells have a lower height value than the current cell, the river instead ends in a sink, signified by a circle.
Have Fun!
Solution code: Digits from row 7, left to right
on 16. November 2023, 15:06 by SquaringSquirrel
Great puzzle, thank you. It was an entertaining and smooth solve.
> Thank you!
on 3. November 2023, 22:13 by Schorsch
Fixed german spelling
on 17. September 2023, 21:20 by apothycus
love this ruleset
on 17. September 2023, 17:11 by Prutsbeest
As with the first puzzle of this kind, great ruleset and fun solve. Thanks!
> Thank you very much!
on 17. September 2023, 17:05 by Schorsch
actually fixed solution code
on 17. September 2023, 17:04 by Schorsch
fixed solution code