Logic Masters Deutschland e.V.

XeonRisq invented a new constraint called Delta Sums and he invited me to help him explore the implications and intricacies of different Delta Sums within the grid. Delta Sums are a mathematically demanding constraint, but they result in some very unusual properties if you can keep up with the mental math they require. There is no shame in using a calculator alongside this puzzle - I certainly did while setting it! ;)

XeonRisq and I both made Delta Sum puzzles to introduce this constraint to the world. Please check out Xeon's puzzle here.
Whereas Xeon wanted to use both row/column Delta Sums and a simpler variant called Delta Quads, I thought it would be nice to have a pure row/column Delta Sum puzzle and Xeon welcomed a dual release to introduce his constraint. Unrestricted Delta Sums can easily become utterly impractical for deductions due to an overwhelming number of possibilities, so I tried very hard to always have a highly constrained Delta Sum available somewhere in this puzzle to keep the solve path reasonable, while still trying to highlight some of the odd properties of Delta Sums.

XeonRisq made a fantastic visual to help explain Delta Sums that I will copy here.
Delta Sums: A number outside the grid gives the sum of the absolute differences between each pair of adjacent digits in that row or column.

I hope you enjoy my Delta Sum puzzle, Wave Pool!

Solve on SudokuPad