private void RemoveUsedPossibilities() { for (var x = 0; x < Game.SudokuSize; x++) { for (var y = 0; y < Game.SudokuSize; y++) { var cellValue = CellsSolution[x, y]; if (cellValue != SudokuElementSolution.InvalidValue) { var elementsAtCell = GetSudokuElements(x, y); SudokuElementSolution.RemovePossibility(elementsAtCell, cellValue); } } } }