I'll add another implementation, Mines from the great sgt-puzzles collection. https://www.chiark.greenend.org.uk/~sgtatham/puzzles/ https://www.chiark.greenend

I'll add another implementation, Mines from the great sgt-puzzles collection. https://www.chiark.greenend.org.uk/~sgtatham/puzzles/ https://www.chiark.greenend.org.uk/~sgtatham/puzzles/ It has an option to "ensure solubility" similar to the one @gergoerdi mentions above.