Step 1: Divide the number into separate digits:
4427 => 4 4 2 7
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
4 to 4 = 0
4 to 2 = 2
2 to 7 = 5
7 to 4 = 3
Step 3: Combine the filters to a string:
0 2 5 3 = 0253