sudoku.

"sudoku." - is a logic-based, combinatorial number-placement puzzle. The objective is to fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 subgrids that compose the grid (also called "boxes", "blocks", or "regions") contains all of the digits from 1 to 9. The puzzle setter provides a partially completed grid, which for a well-posed puzzle has a single solution. ▪ 33 levelsAchievements ▪ 66 Achievements ▪ Full Russian and English Alphabet + Symbols Trading Cards, Badges, Emoticons, Backgrounds (Soon) Music: Chris Zabriskie