Oil-n-Water Quads
by Blobz Open on SudokuPad
- Killer cages
- Quadruples
- Oil and water cages
The brief
Normal sudoku rules apply.
Digits in circles must appear in the surrounding 2x2 area.
Digits in cages do not repeat.
Each cage is either full of "oil" (even digits), full of "water" (odd digits), or a mix of both. In all cases, each "row" within a cage is of just one type (oil or water). Oil floats on water, so even digits will always be in rows above odd digits in mixed cages.