It's a Modular World After All
by FullDeck and Missing a Few Cards Open on SudokuPad
Heartburn
- Killer cages
- Entropy windows
- Kropki ratio
The brief
- Normal sudoku rules apply. - Global modularity: Every 2x2 region must contain digits with three different remainders when divided by 3. - Cages: Digits within a cage cannot repeat and must sum to the value shown in the upper left corner of the cage.