I'm not sure if it's just going over my head, but I cannot find a Sudoku app that utilizes s-pen functionality. By this I mean, treating it like a normal pencil and paper Sudoku where you can write in the numerical values and the app would recognize it. I remember there was one floating around about two years ago, but I can't find it anymore! Any help or suggestions for other s-pen centric apps would be greatly appreciated!