Zipping from Corner to Corner
by FullDeck and Missing a Few Cards Open on SudokuPad
Strong Indigestion
- Zipper lines
- Quadruples
The brief
**Standard Sudoku, Quadruples, Zipper Lines ** - Standard sudoku rules apply: The digits 1 through 9 appear in every row, column, and box. - Quadruples: Digits in a Quadruple circle must be placed at least once in the four cells touching that circle. - Zipper Line: Along Zipper lines, pairs of digits equidistant from the center of the line have the same sum. For Zipper lines of odd length, that sum is the central digit on the line.