Step 1: Divide the number into separate digits:
3632 => 3 6 3 2
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
3 to 6 = 3
6 to 3 = 3
3 to 2 = 1
2 to 3 = 1
Step 3: Combine the filters to a string:
3 3 1 1 = 3311