X Marks the Quad
by FullDeck and Missing a Few Cards Open on SudokuPad
Indigestion
- Diagonals
- Quadruples
The brief
Diagonals, Quadruples - Normal sudoku rules apply. - Diagonals: digits cannot repeat along the marked diagonals. - Quadruples: Each digit shown in a Quadruple circle must appear at least once in the four surrounding cells. If a digit appears twice in the Quad, it must appear twice in the surrounding cells.