Sudoku Solver
Input a solvable sudoku, and it'll spit out a solution! If it's unsolvable, it'll let you know. You can leave empty squares empty, or fill them out with a zero or a dot.
Here is the solution board. If it is full of dots, that means no solution exists! (Sadly, in the current version of the project, the algorithm doesn't detect whether or not the solution is unique).