Sudoku time! Highlighting this neat puzzle featuring only XV sums and kropki dots. Despite having a negative constraint on the XVs, it's far from trivial!
https://logic-masters.de/Raetselportal/Raetsel/zeigen.php?id=000NJC
Grok and Gemini on Sudoku.
It would be an interesting test to give them a Sudoku puzzle that has 2 solutions.