Exponential Puzzle Solver

    public IEnumerator RecursiveTileIterator(int i)
    {
        currently_checking_for_solutions = true;
        numIterations++;
        if(numIterations % 10000 == 0)
        {
            yield return null;
        }
        if(i < (width*height-1))
        {
            if(!lockedTiles[i] && !disabledTiles[i])
            {
                currentState[i] = false;
                if(symbols[i] > 0 && symbols[i] <= 6) tiles[i].symbols[0].SetColor(Color.white);

                //Not part of the above if, just a scope to kill the IEnumerator when we leave it
                {
                    IEnumerator count = RecursiveTileIterator(i+1);
                    while (count.MoveNext()) if(numIterations % 10000 == 0) yield return null;
                }

                currentState[i] = true;
                if(symbols[i] > 0 && symbols[i] <= 6) tiles[i].symbols[0].SetColor(Color.black);

                //Not part of the above if, just a scope to kill the IEnumerator when we leave it
                {
                    IEnumerator count = RecursiveTileIterator(i+1);
                    while (count.MoveNext()) if(numIterations % 10000 == 0) yield return null;
                }
            }
            else
            {
                //just a scope to kill the IEnumerator when we leave it
                {
                    IEnumerator count = RecursiveTileIterator(i+1);
                    while (count.MoveNext()) if(numIterations % 10000 == 0) yield return null;
                    RecursiveTileIterator(i+1);
                }
            }
        }
        else
        {
            if(!lockedTiles[i] && !disabledTiles[i])
            {
                currentState[i] = false;
                if(symbols[i] > 0 && symbols[i] <= 6) tiles[i].symbols[0].SetColor(Color.white);
                if(isSolved())
                {
                     SolutionList.Add(currentState.Clone());
                }
                currentState[i] = true;
                if(symbols[i] > 0 && symbols[i] <= 6) tiles[i].symbols[0].SetColor(Color.black);

                if(isSolved())
                {
                     SolutionList.Add(currentState.Clone());
                }

            }
            else
            {
                if(isSolved())
                {
                     SolutionList.Add(currentState.Clone());
                }
            }
        }

    }