private void Form1_Load(object sender, EventArgs e)
        {
            char[] alphabet = new char[]{'a', 'b', 'c', 'd', 'e', 'f'};
            List<string> list = new List<string>();

            this.F(alphabet, list, "",  0 ,  5 );
        }

        void F(char[] alphabet, List<string> list, string word, int level, int wordLength)
        {
            if (level < wordLength)
            {
                foreach(char c in alphabet)
                    F(alphabet, list, word + c, level +  1 , wordLength);
            }
            else
            {
                list.Add(word);
            }
        }

private void Form1_Load(object sender, EventArgs e)
        {
            int[] alphabet = new int[] {  1 ,  2 ,  3  };
            List<int[]> list = new List<int[]>();

            //this.F(alphabet, list, "aaaaaaaa",  0 ,  5 );

            this.F(alphabet, list, new int[] {  0 ,  0 ,  0  });
        }

        void F(int[] alphabet, List<int[]> list, int[] word)
        {
            int i =  0 ;
            bool bReset = false;
            
            while (true)
            {
                if (i < alphabet.Length)
                {
                    if(!bReset)
                        list.Add((int[])word.Clone()); ;

                    word[i]++;

                    if (word[i] == alphabet.Length)
                    {
                        word[i] =  0 ;
                        i++;
                        bReset = true;
                    }
                    else if(bReset)
                    {
                        i =  0 ;
                        bReset = false;
                    }
                }
                else
                {
                    break;
                }
            }
        }

 while (true)
            {
                if (i < word.Length)