Classic Sudoku Redux

Classic sudoku puzzle * endless (computer generated) puzzles in 4 difficulty levels * many setting options for learning how to play perfectly * (optionally) calculated digits (pencil marks) * show errors/hints * free mode: design your own puzzles or play a newspaper sudoku * highscore optionally: * highlight errors * highlight all occurrences of a selected number * highlight finished numbers digits (pencil marks): * constantly compute all pencil marks as the sudoku changes * calculate pencil marks at start * show marks as numbers or as dots Have fun playing!