First the generator will convert today's date.

Let's say today's date is Saturday, 22/12/2001.

The generator will convert Saturday to 6, and December to 3. Since the date, 22, is not a single digit number it will self reduce it to 2 + 2 = 4. The generator will do the same thing to the year. Here, for example, it will add up 2 + 0 + 0 + 1 = 3.

Next, the generator will process your birthdate. It will divide your birthdate into 3 parts. The day of your birthdate, the month of your birthdate and the year of your birthdate.

So if your birthdate is 08/06/1968. Then your day of your birthdate is 8, your month of your birthdate is 6, and your year of your birthdate is 1 + 9 + 6 + 8 = 24 = 2 + 4 = 6.

Now, to get your first digit of the 4D, the generator adds up your day of your birthdate and today's day number and self-reduce it. For example, further using the above examples, the first digit of the 4D will be 8 + 6 = 14 = 1 + 4= 5.

To get the 2nd digit of the 4D, the generator multiplies the 1st digit with your birthdate month and adds it with today's month number before self-reducing it. For example, 5x 6 + 3 = 33 = 6.

To get the 3rd digit of the 4D, the generator multiplies the 2nd digit with your day of your birthdate and adds it with today's day number before self-reducing it. For example, 6 x 8 + 4 = 52 = 5 + 2= 7.

Lastly to get the 4th digit, the generator multiplies the 3rd digit with your birthyear and adds it with today's year before self-reducing it. For example, 7 x 6 + 3 = 45 = 4 + 5 = 9.

Thus, the 4 digits number is 5679.