Step 1: Divide the number into separate digits:
9344 => 9 3 4 4
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
9 to 3 = 6
3 to 4 = 1
4 to 4 = 0
4 to 9 = 5
Step 3: Combine the filters to a string:
6 1 0 5 = 6105