The grid consists of a 9x9 Sudoku plus a row and column of sandwich clues.
Standard Sudoku rules apply. Sandwich clues specify the sum of digits between the 1 and the 9 along a row, column, or diagonal indicated by a small arrow.
Here is an example of legal F type pentominoes. Note the numbers placed in the center cells may be Sudoku digits or Sandwich clues.
It is possible to tile an infinite plane with any of the 12 pentominoes. Here is an example of tiling that obeys the rules above using P-type pentominoes:
Lösungscode: Row 5, Column 7 of the Sudoku (18 digits total)
am 18. August 2020, 16:30 Uhr von psams
@bosjo Thank you for your generous comment. Sometimes the solvers find options the setter missed! I could disambiguate the tiling, but I think I will leave it unchanged for those looking for a challenge.
If your first tiling fails the sudoku, try again, but not more than twice!
am 18. August 2020, 15:58 Uhr von bosjo
The tiling bit is the difficult part — I found three ways of getting the tiles with the correct colours; two of them were hopelessly broken when adding the center digits, and the third I thought was broken when I couldn't put a certain digit on the diagonal. With that misunderstanding cleared up, it was fairly straight forward from that point.
A nice puzzle, but with a few unusual and unclear details in the initial description. I particularly liked the "double impossible ending", resolved by one of the innocent looking requirements. I spent a long time trying to solve this, but I guess the author spent far more making this intricate machinery work.
If you like pentominoes, which I do (or at least did...), then you have to try this puzzle!
am 7. August 2020, 15:00 Uhr von RockyRoer
What are the bigger numbers along the bottom and right side? Sums of centers? Nevermind... see it now... sandwich clues.